iPad attends Meetings

30 04 2013

The iPad offers great benefits because of it’s form factor and mobility.
The Retina display allows relaxed working over a long time.
It’s a complete device without the need of any peripherals.

So it’s predestined for many tasks where a powerful processor, a perfect display and a reliable operating system is required.

Business or other meetings today are a bit different from old-fashioned lectures at universities decades ago or solo actions of Monday-morning quarterbacks.

Let’s talk about some aspects where the iPad may improve the results of meetings and enforce the participation of the meeting members.
The technical equipment is geared towards extensive communication between the members and supports presentation of ideas on an ad-hoc basis.

Additional support for information exchange between iOS devices of the meeting members is provided by a new app named INSTASHARE, which supports direct file transfer between iOS devices Macs and PCs (Beta).
For explaining and clarifying propositions and opinions each iOS device can be connected to a Beamer or a TV to show secondary sources, ideas, doodles and stickies.

So a highly flexible environment is established for growing Big Onions with relatively less financial and technical efforts.

This environment follows the principle of least effort which says:

People will use the tools that are most familiar and easy to use to find acceptable results. For example, one might consult a generalist co-worker down the hall rather than a specialist in another building, so long as the generalist’s answers were within the threshold of acceptability.

The iPad provides this approach (via Internet, company servers, cloud storages, locally saved documents) to all the information which might be relevant to achieve the best results even if the present knowledge of the audience is insufficient to clear up some details.


Practical experience …

This mind map (Opti.Tax) was created during a meeting about the usage of a software product which supports the upload of balance sheets to the tax authorities. This procedure is required by law in Germany beginning with the accounting year 2014.

One training participant documented the lecture with the help of a mind map shown below.
Others created questions and hints with Apple’s iWork app PAGES regarding the usage of the software product as well as suggestions for feature updates.

The documents have been transferred to the iPad and added the mind map’s branches. Transfer was done with Instashare (see the brief description below).


Instashare …

Exchanging files of any type between meeting members can be done with a new app, released in February 2013, available at Apple’s App Store.

Instashare is an aptly named utility that lets you instantly share files between iOS devices, Macs, and Windows PCs (Beta).

Sharing is quite simple. Once you’ve connected Instashare on your iDevice with another iOS device or a Mac companion app.
On the iOS device all connectable devices appear on the right side and the file list on the left side. You then transfer files by Drag and Drop from left to right. Instashare uses a WiFi or even a Bluetooth connection.

In addition, you can transfer files of any file type from a Mac to your iOS device and vice versa. Files received by a Mac appear in the Downloads folder, while those received by an iOS device can be found in Instashare’s local app folder.


Meeting whiteboard …

You may also try the app Anywhere Pad. Once you create a meeting and add a blank whiteboard page meeting members can add sticky notes and freehand drawings.
I have no experiences with this app, so I cannot rate it. At the time I wrote this article there were no user ratings at the App Store.

Downloads …

The mind map ‘Apple Devices in Meetings’ created with iThoughts for iOS can be downloaded here:

The Apple group on Biggerplate.com

Map as a PDF

Map in ITMZ file format (iThoughts)

Map in MMAP file format (MindManager)

Map in XMIND file format (XMind)

Back to the roots

27 04 2013

You find sophisticated apps in Apple’s App Store and those which are shining examples for simplicity and plain designs.

In this article I talk about

  • Discount Spreadsheet by Luminant Software
  • PlainText by Hog Bay Software

Why? …

Discussing simple issues with young people is the first step to improve knowledge. Knowledge is the basis of creativity. So the two main targets of teachers must be to transfer knowledge and initiate further discrete thinking of their pupils.

Working with a simple app initiates thinking about the need of further features.
An originally created ‘concept map’ as a feature description for those using the app later can be extended to a map with the typical properties of a mind map by adding elements of brainstorming.

By the way, pupils learn an alternate technique of summarizing results of their learning process, alternate to commonly used textual descriptions, spreadsheets, or images.

So the learning process might look like

  • Learning the use of the app by using a pre-created concept map
    This concept map can be seen as the documentation of the app.
  • Developing ideas for improving the features
    In a first step pupils build a new topic adding their ideas for
    – new must-have features
    – new nice-to-have features
    using special properties for new topics (color, icons, etc.)

    In a second step these new features may be dragged into the concept map by keeping the color of the new topics.

The benefits of combining a concept map with elements of a mind map are

  • Existing features stay always in the focus
  • New features must be brought into line with existing features

Discount Spreadsheet …


It’s simple with a plain design that lets the users focus on the relevant tasks.

So I think it’s a perfect app to explain the basics of creating spreadsheets to young people.

Learning targets could be …

  • learn the common actions cut, copy, paste, undo and redo which are provided by all operating systems
  • build a sum with cells in a column or row
  • enter a simple expression where the arguments are cells
  • drag a formula for a row/coulmn to another row/column and see that a spreadsheet app automatically adjusts the cell coordinates in the formula to the destination row/column
  • access the iOS app specific folder via a browser by using a http address

Here is a mind map containing a full feature description of the app.
The map was created with the app iThoughts by Craig Scott, UK.


You may download it here as a PDF

Discount Spreadsheet (PDF)

Visit the mind map library

Biggerplate, UK (group APPLE)

to download further mind maps related to Apple’s iOS devices.

PlainText …

This app can be compared with Microsofts dinosaur app EDITOR.

I myself use PlainText for writing down ideas for blogs. There are no functionalities available, not even formatting, so you have to completely focus on the contents.
Saving of text is automatically and frequently done by PlainText in a folder called PlainText on Dropbox.

It’s all automatic except writing the text.


This app is, like Spreadsheet, suitable for teaching children in writing texts.

Learning targets could be …

  • using the on-screen-keyboard
  • learning orthography by turning off the iOS setting ‘Check spelling
    (Settings – General – Keyboard – Check Spellings)
  • learning collaboration by using the same Dropbox account on two or more devices
    The pupils should recognize that relevant functionalities for collaboration are missing, e.g. who edited existing text and what part of the text was changed.
  • developing a mind map with preferable extensions to a more powerful text editor

Summary …

Learning to use a simple app initiates the creativity to extend the basic features.
This learning process can be combined with learning a new technique which brings the activity to a very personal level.

It’s because a touchscreen is much nearer to human activities than any other device or textbook could be. What we do is mostly what we do with our hands. It’s our first approach to new things. Creating artworks, modeling new devices or writing down all the ideas leading to the E=m c c equation on a sheet of paper while walking through the room and reflecting our thoughts is almost always done by hand.
So it’s obvious that using a mind map in schools improves the motivation of pupils to intensively get in touch with a topic.

Thanks for visiting http://iNotes4You.com.
I hope you come back soon.

Network (3) Port Forwarding

25 04 2013

Parts (1) and (2) of my articles about networks gave you some basic knowledge about networks and discussed the possibility to connect from the LAN to the WAN or in other words from the devices at home to the webservers in the outer world.

The reverse way, connecting from WAN to LAN, is basically not possible. Only in case of requests from a device within the LAN data goes the reverse way, e.g. entering an URL like http://iNotes4You.com as the request and getting the answer (the website content) delivered by WordPress.com servers.

The main reasons why a WAN-LAN connection won’t work:

  • 1 Most of the ISPs (Internet Service Providers) assign varying IP addresses to your connection so that it is not possible to keep a stable connection over the time.
  • 2 For security reasons nobody should be able to compromise your LAN.
    So a Firewall/Router will not accept incoming requests which were not initiated by a device within the LAN.


The solution is Port Forwarding an applications communication with another application.

Dynamic DNS …

The first problem of varying WAN IPs can be solved by using a service called Dynamic DNS (DDNS). Some companies offer this service without charging.

For example you can register at no-ip.com. After completing the registration process you can define a hostname and download the so-called DUC software (Dynamic Update Client) which has to be installed on the computer you want to connect to.


The main idea is to get a HOSTNAME which can be used instead of the varying WAN IP. The DUC client on the computer inside the LAN frequently determines the actual WAN IP and transmits the result to the DDNS provider. Your request from outside your LAN first is transmitted to your DDNS provider via the HOSTNAME. DDNS returns the actual WAN IP of your LAN and a connection can be established.

So DYNAMIC DNS SERVICE provides a constant ALIAS for a varying WAN IP of your LAN.

Opening the firewall …

You already know that data on the Internet is sent to and from IP addresses. Sending or receiving data is done on ports. Ports are virtual pathways on which Internet data flows.

For a Watchguard SOHO Firewall a custom service has to be defined and the related traffic has to be allowed. The service must include the definition of an IP of the computer you want to connect to as well as the port for communication.


While things may differ slightly depending on your Firewall’s/Router’s firmware, the below mentioned fields are pretty standard:

  • Application or Service Name
    The name of the application you’re forwarding this port for. You can use any descriptive text you want—this field is here to help you remember why you set this up; like the name suggests, you normally want to use the name of the application you’re setting up port forwarding for. I’s a good idea to also include the computer’s name along with the service if port forwarding is used for the same applications on different computers.
  • Port to
    ‘Port to’ is the port on your local IP address. If you were setting up VNC for a local computer, you’d fill this in with 5900 as that’s the standard port number for VNC services.
  • Port from
    ‘Port from’ is the port on your external IP address. Generally you use the same port as entered in ‘Port to. This works just fine when you’re configuring only one machine for one type of service. But say you wanted to be able to remotely access two or more computers using VNC. If you used 5900 on a single, external IP address they would be in conflict. The router would see a request for port 5900 and not know which Local IP address should handle that request since the port forwarding table has two. To solve this problem, you can use the standard port for one and not for the other—kind of like an apartment building has a single address but multiple apartments. You can use port 5900 for one and 5901 for the other computer. In that case you have to first set the port (the computer you want to access) when using VNC on an external IP address. This way you can set up identical services with a single External IP and different Local IPs without conflicts.
  • Protocol
    This is where you specify whether or not your service uses the TCP protocol, UDP protocol, or both. When you look up your ports you’ll also want to make note of the protocols used. In most cases it will just be TCP.
  • IP Address or Service Host
    This is where you specify the LAN IP of the computer you want to access. You can easily find this information in your computer’s network settings. The IP address will generally be in the 10.0.x.x, 192.168.x.x, or 172.31.x.x format. Because these IP address are generally dynamic (changing over the time), you have to set up static IPs or so-called DHCP reservations.
  • Enable
    You need to enable the port forwarding rule (on Watchguard routers you do it by setting the rule to ALLOW). By using DENY you are able to save the rule but it won’t be active or function in any way.

The firewall is now opened for authorized incoming traffic to a specific computer using a specific port.

The communication is done by the VNC Server software which can be downloaded from the RealVNC website.

After installing the DUC client software from No-Ip and the VNC server software from RealVNC on your PC it looks like this:


VNC viewer on an iOS device …

To configure the VNC Viewer app on an iOS device you just have to enter the HOSTNAME, the PORT for communication and the credentials you defined in the VNC Server software on your computer.


Summary …

The connection to a computer inside a LAN from an iOS device outside the LAN works with a

  • Dynamic DNS account and an Update Client (DUC)
  • Configuration of the firewall for a specific computer and a specific communication port
  • Server software (VNC Server) on the computer
  • Client software (VNC Viewer) on the iOS device

In a typical small office environment, a router assigns private network addresses to internal computers while the router gets a public IP from the ISP.
If the public IP is not static, Dynamic DNS services must be used to configure the VNC Client
by using the Dynamic DNS address instead of an IP address.

Connection to a computer in the LAN requires an installation of VNC Server software.
A unique port number must be assigned to each computer that should be reached from outside the LAN.

Useful links …

Former articles about networks

Network (2) Apple Airport Router

Network (1) Addressing

If you want to use Port Forwarding you should visit


Port Forwarding VNC on Apple Airport

You will find the settings for many Soft- and Hardware products as well as a software product called PFConfig which supports automatic configuration (29.29$).

Network (2) Apple Airport router

22 04 2013

Part (2) of my articles about networks is about the installation of an Apple Airport Extreme router (APE). The internet connection is established via a Cisco modem which is connected to a cable internet plug connection.

You remember, a router is the device which mainly does the addressing within your local area network (LAN) that means, assigns IP addresses to all devices. Furthermore it handles the communication between a device inside the LAN with another device as well as the communication between LAN devices and ressources outside your LAN e.g. webservers like Apple’s iCloud servers or WordPress servers where the blog http://iNotes4You.com is hosted.

The main content of this article is also available in German and refers to the German Cable Internet provider UNITYMEDIA. It can be downloaded from my page Documents.

Requirements …

  • Modem with cables
    Usually you will het the modem from your ISP.
  • Apple Airport Extreme router
    The description is also valid for an Apple Airport Express router or Apple’s Time Capsule, a router with an integrated Harddisk.
  • Ethernet cable
    for connecting the APE to the modem
  • Apple’s app AirPort Utility for iOS
    You can download the app from Apple’s App Store for free.
  • Optional Apple’s app Airport Utility for Mac/PC
    The iOS app Airport Utility has limited capabilities and not all settings for your network can be done with this app. For example: You cannot set the signal strength (10-100%) with the iOS app.

Setting up the APE router …


Follow these steps in the order specified.

Step 1 Connect the modem to the multimedia connector with a coaxial cable.

A modem (modulator-demodulator) is a device used to connect a computer or router to a telephone/cable line to allow the computer to connect to the Internet. It modulates a carrier signal to encode digital information, and also demodulates such a signal to decode the transmitted information. The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data.

Step 2 Connect the modem to the power supply.

Wait until the LEDs indicate a functioning connection to your ISP.
It may take up to 30 min.

Step 3 Connect the APE to the modem with an Ethernet cable.

Ethernet cable
Ethernet cabling is standardized. If you go to a store you may find a variety of “categories” of cabling. These categories tell you the quality of the cabling. The quality determines, essentially, how much the cable can handle. Recommendation: Cat 6 – works for 10/100/1000Mb.

Step 4 Connect the APE to the power supply.

Here we go.
The configuration with any iOS device and the helper apps Settings and AirPort Utility starts.

Open Settings on your iPhone or iPad and tap on WiFi.
The APE already is sending signals so that your device suggests the set up of a WiFi network.


Tap on the right-pointing arrow to set up an AirPort basestation.
Enter a name for your network and set a password. Other users like your neighbors, if not too far away, will see this name as an additional WiFi network. Use a strong password for joining this network.


Tap on Next and that’s all.
Your new WiFi network will connect all your devices with the internet after entering the password you set for your network.


Summary …

Apple’s ZEROCONF technique minimizes your efforts to install a usable internet access.

Zero configuration networking (zeroconf)
is a set of techniques that automatically creates a usable Internet Protocol (IP) network without manual operator intervention or special configuration servers.
Zero configuration networking allows devices such as computers and printers to connect to a network automatically. Without zeroconf, a network administrator must set up services, such as Dynamic Host Configuration Protocol (DHCP) and Domain Name System (DNS), or configure each computer’s network settings manually, which may be difficult and time-consuming.

Look at the details to get a deeper understanding of what happened.
To see the details of your own WiFi network go to Settings – WiFi and tap on the right-pointing blue arrow of you network. Go to the bottom and tap on ‘Manage network’. This will open the Airport Utility. Airport Utility can be used to individualize the configuration.

Regarding to my blog Network (1) from April 20 you will now understand the configuration details set by the APE:

    the APE acts as a DHCP server and assigns private IP addresses (10.0.1.x) to all devices joining the WiFi network after entering the password.
  • NAT ON
    the APE does the network address translation that means, NAT converts your private LAN IPs into a external WAN IP
  • Security
    the APE encrypts all WiFi network traffic with WPA2
    (Wi-Fi Protected Access II (WPA2) is a security communication protocol developed by the Wi-Fi Alliance to secure wireless computer networks)

This slideshow shows all settings displayed in Apple’s app AirPort Utility:

This slideshow requires JavaScript.

In addition to the automatic configuration I entered the following settings:

  • Reservations for IP addresses
    the APE reserves an IP address for all devices. Reservations are useful if you want that the DHCP feature of your APE assigns a fixed IP to your devices. Otherwise DHCP is free to assign any free IP address in the range – every time you join your network.
  • 5 GHz network
    The APE works in the 2.4 and 5 GHz frequency band. The iPad is able to connect on the 5 GHz band and I named this (second) network as ‘Apple Airport 5 GHz’.
    If you have interference problems with other WiFi networks you may vary the channel or move over to the 5 GHz network.
  • With the help of Airport Utility for PCs I additionally limited the signal power to 50% which is enough to get connected in all rooms and hampers other WiFi capable devices outside my home to detect my network.

The result is a working internet connection checked by the app Fing which is available at Apple’s App Store.


Problems …

A well-known problem may arise and is frequently mentioned in several forums.
There is an easy way to fix it. Just do what Apple tells you in the help text.


Connecting to a DSL service provider …

If the Airport Extreme router has to be installed in a Microsoft Windows network with an existing internet connection via DSL some changes in the settings of the APE are necessary.
It’s because the server of the Windows network is the DHCP server now and therefore assigns the IP addresses instead of the APE.

But don’t get nervous. The strategy of Apple’s Zeroconf is to make it easy for you. And it’s easy because the APE automatically collects relevant informations about the existing network and then sets most of the relevant values automatically.


The last article about networks will answer the question how to get into a private network with varying WAN IPs from outside the LAN e.g. For accessing files on a computer inside the LAN.

Thanks for visiting http://iNotes4You.com.

Network (1) Addressing

20 04 2013

The articles about networks are written for my readers who are not familiar with the terminology, the functionalities and the cooperation between devices in a network environment.

Part (1) explains the basics of networking. Experts should overlook some verbalization because I want to keep it very simple.

If you want to communicate with other people far away from you, you need an address. It can be a postal address, an E-Mail address or a phone number. In any case the address has to be unique to ensure that your message will be delivered to the person you want to communicate with.


As you can see I left out the addressing method of the corresponding transmission of a PDF file from one of your devices to a Dropbox cloud storage account.
Addressing we use for letters is not appropriate for a computer network as it can be written in different ways up to the country’s conventions. Furthermore there is no fixed location where data are stored. On a day it can be a webserver in Australia and a day later it possibly can be a webserver in India.
So the device address must be more like a GPS address which is uniquely written all over the world with the additional possibility to forward an existing address to a new address without noticing the users. To do so a complex organizational computer infrastructure has to be established which transmits requests to the right recipients wherever they are actually located.

All network devices around the world use an IP address for identification purposes. It usually consists of 4 numbers separated by a dot (

An IP address (Internet Protocol address) is an assigned numerical label that is used to identify devices on computer networks. Think of it like this: An IP address is to a computer what a telephone number is to an iPhone. Each computer can stand alone without its respective IP address. However, if you want to communicate with other computers from yours, you will need an IP address.

  • An IP address is a 32 bit binary number divided into four sections by dots.
  • Each part of an IP address is called on octet.
  • As 255 is the largest number which can be represented with 8 bits each octet can range the range from 0 to 255.
  • For LANs the following IP addresses are reserved by RFC 1918: – – 172. 31.255.255 –

An IP address serves two principal functions: host or network interface identification and location addressing. Its role has been characterized as follows: “A name indicates what we seek. An address indicates where it is. A route indicates how to get there.”

Here you can see an example. It’s my small home configuration, a WiFi network with some Apple devices where the boss for addressing all devices is an Apple Airport Extreme router.


As you can see this network has no connection to the outer world at this time. So this system allows basically the use of any combination of numbers for addressing the devices.

Severe problems would arise if you want to contact a network outside this local area network (LAN) e.g. a webserver in another country which provides a website you are interested in. It cannot be assured that the address of this computer is unique. So your request might wander around the world with uncountable answers.

In my articles about networks you often are confronted with the expression protocol. What is a protocol?

A communications protocol is a system of digital message formats and rules for exchanging those messages in or between computing systems and in telecommunications. A protocol may have a formal description. Protocols may include signaling, authentication and error detection and correction capabilities. Communications protocols have to be agreed upon by the parties involved. To reach agreement a protocol may be developed into a technical standard.

Look at the first image of this article.
We can talk about a Postal Protocol where the postal address has to be defined as name, street (or PO box), city, ZIP code and country. It’s just a convention about the way how an address has to be written and what kind of information should be included.

LAN and WAN …

To solve this problem, a LAN (where IP addresses are free to choose) can be connected to other LANs by using a worldwide unique wide area network IP address (WAN IP address). Your Internet Service Provider (ISP) assigns a WAN IP address to your router so that requests from a device inside your LAN is transmitted with this WAN IP and the recipient can answer using your WAN IP as the destination address.

Here is the WAN IP taken for my local area network some weeks ago.


My ISP is a German Cable Internet Provider. Like most other ISPs the company assigns varying IP addresses to my connection. My IP address is therefore called a Dynamic IP address. It may vary from hour to hour or day to day. So usually I cannot reliably reach any device inside my LAN without looking up the actual IP address. This problem will be discussed later.

Look here for a more detailed view on LAN and WAN IPs and what your devices have to do when you connect to the internet e.g. request for a website.


You can see that there are several devices with different LAN IPs but only one WAN IP.
So it has to be cleared up how the information requested by a specific device is delivered to this device. NAT (Network Address Translation) does it.

In computer networking, network address translation (NAT) is the process of modifying IP address information in IP packet headers while in transit across traffic routing devices.

If you enter the address of a website e.g. http://iNotes4You.com you might argue that this format is not the format of an IP address as mentioned above. You are right and some further functionality is needed to convert this human-friendly address into an IP address.
This service is called DNS (Domain Naming System).

The Domain Name System (DNS)
is a hierarchical distributed naming system for computers, services, or any resource connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities. Most prominently, it translates domain names meaningful for users to the numerical IP addresses needed for the purpose of locating computer services and devices worldwide. By providing a worldwide, distributed keyword-based redirection service, the Domain Name System is an essential component of the functionality of the Internet.
An often-used analogy to explain the Domain Name System is that it serves as the phone book for the Internet by translating human-friendly computer hostnames into IP addresses. For example, the domain name http://www.example.com translates to the addresses Unlike a phone book, the DNS can be quickly updated, allowing a service’s location on the network to change without affecting the end users, who continue to use the same host name. Users take advantage of this when they recite meaningful Uniform Resource Locators (URLs) and E-Mail addresses without having to know how the computer actually locates the services.

Ports …

You already know that data on the Internet is sent to and from IP addresses. Sending or receiving data is done on ports. Ports are virtual pathways on which Internet data flows.

If we think of an IP address as a telephone number (an identifying number that allows communication between two locations), then we can think of ports as telephone number extensions. Suppose you wanted to make a telephone call to a major corporation like Apple. If Apple only had one simple telephone line it would take a very long time for your call to finally get through. However, by using telephone number extensions, Apple can channel incoming calls to the proper locations and as a result handle many calls on one line as opposed to just one call.
Ports are like telephone number extensions as they allow multiple pieces of data to flow back and forth on a single IP address. In fact, port numbers are appended to the end of IP addresses just as extensions are appended to telephone numbers.

In other words, ports are numerical identifiers that make it possible for you to check your E-Mail and browse the web at the same time. Technically speaking, this is possible because browsing the web traffic generally uses port 80, secure website connections use port 443, and getting your E-Mail generally uses port 110.

Technical Facts
Ports are a 16-bit number can range from 1-65535.
TCP and UDP packets specify the port on which they are to be sent in their packet header.
The ports that a given application uses are generally set by the programmers of that application.the purpose of ports is to uniquely identify different applications or processes running on a single computer and thereby enable them to share a single physical connection to a packet-switched network like the Internet.

The protocols that primarily use ports are the Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP) of the Internet Protocol Suite. A port is identified for each address and protocol by a 16-bit number, commonly known as the port number. The port number, added to a computer’s IP address, completes the destination address for a communications session. That is, data packets are routed across the network to a specific destination IP address, and then, upon reaching the destination computer, are further routed to the specific process bound to the destination port number.
Note that it is the combination of IP address and port number together that must be globally unique. Thus, different IP addresses or protocols may use the same port number for communication; e.g., on a given host or interface UDP and TCP may use the same port number.

Ports in Relation to IP Addresses …

Remember at the top of this page when it was mentioned that ports are appended to the end of IP addresses just as extensions are appended to telephone numbers? There is a specific syntax for appending port numbers to IP addresses and it is as follows:
(IP Address):(Port Number) or..

Notice the colon acting as a separator between the IP address and the Port Number. Port Numbers are appended to the end of all IP addresses whenever data is sent.
Why don’t we see a port number appended to the end of web addresses?

There are a few commonly used port numbers. Web traffic uses port 80 and is in fact so common that port 80 is assumed to be appended to the end of a web address by your internet browser and thus can be left off. You can test this by typing google.com:80 into your browser’s address bar. When you press enter, you should go straight to Google. Now, try typing google.com:6060 into your browser’s address bar. When you press enter, you will not be connected to Google.


There is still some information missing. Who assigns IP addresses?

The Dynamic Host Configuration Protocol (DHCP) is a network protocol that is used to configure devices which are connected to a network so that they can communicate on an IP network. The main task of a DHCP server is the assignment of unique IP addresses to all devices within the network. In a typical private LAN, a router is the DHCP server while clients are tablets, computers or printers. The router receives information through a modem from an internet service provider which also operates DHCP servers where the modems are clients. The clients request configuration settings using the DHCP protocol such as an IP address, a default route and one or more DNS server addresses. Once the client implements these settings, the host is able to communicate on that internet.
The DHCP server maintains a database of available IP addresses and configuration information. When the server receives a request from a client, the DHCP server determines the network to which the DHCP client is connected, and then allocates an IP address or prefix that is appropriate for the client, and sends configuration information appropriate for that client.

Summary …

  • IP address
    a number like as an identification of a device within a network
  • LAN
    the local area network
  • WAN
    the wide area network connecting LANs
  • NAT
    the replacing of LAN addresses by WAN addresses
  • DNS
    the renaming of human-friendly addresses into IP addresses and vv.
  • DHCP
    the system which configures devices especially assigns IP addresses
  • Protocol
    a convention how to communicate within a LAN or WAN

Thanks for reading my blog.
If you have any questions don’t hesitate to contact me via my About page or a comment on this article.

Camera beaming

17 04 2013

Sometimes you have to watch what is happening at another place. You can do this with a camera installation or with an iOS device and the app AirBeam by Appologics UG, Germany.

AirBeam for iOS is a Universal App that means if you buy it in the App Store it can be installed on all of your iOS devices without buying it for each device.

AirBeam turns the camera equipped iDevices or Macs into a flexible remote monitoring system. You can use it as a baby phone, a surveillance camera, a fly cam in your remote control toys, an ad-hoc video observation of a running machine, etc.


If there is only one iOS device available (the recording device) the camera input of this device can be viewed with any browser by entering the IP address displayed on the iOS device where AirBeam is installed.

It works within a WiFi network as well as from far away locations via an internet connection to a device in a LAN by using Port-Forwarding.

AirBeam FAQ Port Forwarding
AirBeam’s autodiscovery mechanism only works when all your devices are in the same local WiFi network. If you want to connect to your camera at home from anywhere in the Internet (or from a cellular network), you first need to configure Port Forwarding in your WiFi router at home. Otherwise the router’s integrated firewall will block all incoming connections from the outside world. There are two ways to configure Port Forwarding:
AirBeam can automatically configure Port Forwarding within your router. Prerequisite is that your router supports and has enabled Universal Plug and Play (UPNP) or Apple’s NAT-Port Mapping Protocol. In this case just switch on “Port Mapping” in AirBeam’s general settings page. If successful, a small cloud icon on AirBeam’s camera view will indicate that the camera is reachable in the Internet and you will see the public addresses by touching the icon. Just use a browser or AirBeam’s “manual connect” button to connect to these addresses from anywhere. As the public IP address of your WiFi router might change from time to time (depending on your Internet Service Provider), it is recommended to use a free dynamic DNS service like http://www.no-ip.com to be able to access your camera with a constant hostname.

For the recording device a motion and audio detection can be activated. If an object starts moving or the microphone detects audio signals a video recording on the receiving device can be started.
Furthermore an E-Mail with an optional attached video can be sent automatically to a recipient whose E-Mail address is configured in the Settings of the app.

On the iDevice receiving video and/or audio signals the integrated camera light can be turned on and off.

The controlling device may connect to different other devices. Each recording device is displayed on the controlling device and you just have to tap on the device’s icon to switch to it’s camera.

On the Mac …

With AirBeam Pro you can share your Mac’s camera and microphone and follow it remotely in a browser or with AirBeam for iOS on your iPhone, iPad or iPod.
Besides camera sharing, AirBeam Pro brings also all other features known from the iOS App to your Mac, for example motion or audio controlled video recording in HD quality.

How it works …

In this description iPhone is the recording device and iPad the controlling device displaying the camera input of iPhone. It works vice versa as well.

  • Install AirBeam on an iPhone and an iPad.
  • Open AirBeam on both devices.
    On the main screen both devices will show the message ‘Searching for cameras…’.
  • On the iPhone (or iPad) tap on the camera icon.
    This activates the camera and sends a Ready-Message to the other device with the devices name.
  • On the iPad tap on the name of the recording device.
    In this example it’s the iPhone and you will see what iPhone’s camera is recording.


Options on the controlling device …

To control the recording device the following options are available:


Settings …

An overview of the Settings of AirBeam shows you some more details about different purposes you may use the app for.

Summary …

After checking all announced features the app gets a rating of 5 stars.
There is just one bug which has to be fixed. After connecting to a device the brightness of the controlling device is set to it’s minimum and you have to reselect the preferred value.

Location-based services

14 04 2013

A location-based system is a system of satellites and earth-based stations that provide geo-spatial positioning with global coverage (GNSS=Global Navigation Satellite System). Small electronic devices with appropriate receivers may determine their location (longitude, latitude, and altitude) to within a few meters using time signals transmitted as electromagnetic waves from satellites and pseudolites.

Pseudolite is an abbreviation of ‘pseudo-satellite’, used to refer to an earth-based station which operates like a real satellite. Pseudolites support satellite-based positioning in case of blocked, jammed or simply missing GPS signals.

A simple 2D method …

To understand how the location of objects can be achieved look at this method which was developed about 500 years ago, the triangulation method.


The math is relatively easy but the prerequisites definitely do not meet the requirements when walking through the streets with an iPhone. You will not find reference points like lighthouses when climbing up the Everest, moving through the Everglades or driving through Australia’s outback.
And moreover it’s a 2-dimensional static method which doesn’t help to fix the location of an object in 3 dimensions, that means to fix the longitude, latitude, and altitude.

A complex 3D method …


Using many satellites fix all these problems as 3 or 4 of them can be ‘seen’ from every location on the earth. The math to localize objects with satellites is complicated so just look at this image and possibly read the more detailed notes or look on this website and I’m sure you will be back at iNotes4You within a part of a second.

GNSS Positioning Calculation

The details …

The satellite broadcasts a signal that contains orbital data (from which the position of the satellite can be calculated) and the precise time the signal was transmitted. The orbital data is transmitted in a data message that is superimposed on a code that serves as a timing reference. The satellite uses an atomic clock to maintain synchronization of all the satellites in the constellation.

The receiver compares the time of broadcast encoded in the transmission with the time of reception measured by an internal clock, thereby measuring the time-of-flight to the satellite. Several such measurements can be made at the same time to different satellites, allowing a continual fix to be generated in real time using an adapted version of trilateration.

Each distance measurement places the receiver on a spherical shell at the measured distance from the broadcaster. By taking several such measurements and then looking for a point where they meet, a fix is generated.


However, in the case of fast-moving receivers, the position of the signal moves as signals are received from several satellites. In addition, the radio signals slow slightly as they pass through the ionosphere, and this slowing varies with the receiver’s angle to the satellite, because that changes the distance through the ionosphere. The basic computation thus attempts to find the shortest directed line tangent to four oblate spherical shells centered on four satellites. Satellite navigation receivers reduce errors by using combinations of signals from multiple satellites and multiple correlators, and then using techniques such as Kalman filtering to combine the noisy, partial, and constantly changing data into a single estimate for position, time, and velocity.

Location services on iOS devices …

Location Services allows location-based apps and websites (including Maps, Camera, Safari, and other Apple and third-party apps) to use information from cellular, Wi-Fi, and Global Positioning System (GPS) networks to determine your approximate location.

For example, an app might use your location data and location search query to help you find nearby coffee shops or theaters, or your device may set its time zone automatically based on your current location. To use features such as these, you must enable Location Services on your device and give your permission to each app or website before it can use your location data.

For safety purposes, your iPhone’s location information may be used for emergency calls to aid response efforts regardless of whether you enable Location Services.

Apps using location services …

  • Camera
    assigning the actual location if you make a photo
  • Find my iPhone
    locating your devices on a map
  • GPS Toolbox
    locating the actual position and saving them in a database

GPS Toolbox …

GPS Toolbox by Audama Software Inc. is a location-based tool for Apple’s iOS devices.

This app provides a variety of GPS and map related tools which enable you to save locations to exportable lists, convert between coordinate formats, and view different map formats (road, satellite, hybrid, or terrain maps) from both Google maps and Bing maps. These features allow you to do things such as:

  • Find GPS coordinates for a location without ever going there.
  • Find what is located at a given GPS coordinate.
  • Map out a list of locations (such as a hiking route) before heading out.
  • Compare map and satellite data from multiple sources (Google and Bing).
  • Create location lists and load them into other programs such as Google Earth.
  • Create location lists and load them into other third-party GPS devices.
  • Locate, view, and convert between GPS coordinates in any of the following formats:
    Decimal degrees, Degrees/minutes, Degrees/minutes/seconds, UTM, MGRS.
  • Manage a collection of GPS points within data files. These data logs can be easily viewed, edited and exported. The following export formats are currently supported:
    Tab delimited, Comma separated values (CSV), GPX, KML, KMZ, HTML tables.
  • Additional features include viewing and saving the current GPS data as well as converting between GPS coordinates and physical addresses.

This gallery shows you some features of the app and the locations I have been. Some of these locations have been recorded with the app others have been entered manually because at the time I visited these places Apple was in the middle of its life crisis and far far away from purchasing smartphones or tablets.

Apple’s privacy policy …

If you use location services on you iOS device look here for informations about your privacy.

Apple Inc. , May 21, 2012
Location-Based Services
To provide location-based services on Apple products, Apple and our partners and licensees may collect, use, and share precise location data, including the real-time geographic location of your Apple computer or device. This location data is collected anonymously in a form that does not personally identify you and is used by Apple and our partners and licensees to provide and improve location-based products and services. For example, we may share geographic location with application providers when you opt in to their location services.
Some location-based services offered by Apple, such as the “Find My iPhone” feature, require your personal information for the feature to work.

Links …

iPhones dining habits

LG: Location based Services for Mobile

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