2. What does LinkConnect do?
Makes a dumb product smart by creating an RS232 tunnel across a mobile network. No special software required at either end of the link to establish network connection. No knowledge of how to establish and maintain a data link on mobile network required.
Only user configuration required is set up of
Baud rate / No data bits / parity
Client / server mode
IP address & port number
Setup is via SMS or a PC based configuration utility
IP Connection made and kept alive automatically
No need to know any mobile network settings

3. Network connection settings
All mobile network are assigned a Mobile Country Code (MCC) and a Mobile Network Code (MNC).
Mobile Country Code is 3 digits – UK is ‘234’
Mobile Network Code is 2 or 3 digits – Vodafone is ‘15’
Operator code 5 or 6 digits [country code (3) + network code (2 or 3)]
Vodafone
O2 – 23402, 23410, 23411

4. Network APN settings
All mobile networks have a public Access Point Name (APN) for generic use and these are standard in each country. This is the gateway that connects the mobile network to the Internet.
UK Vodafone public APN – ‘internet’, username – ‘web’, password – ‘web’
UK O2 public APN – ‘mobile.o2.co.uk’, username – ‘mobileweb’, password – ‘password’

5. Automatic APN settings
Detect network id and lookup APN details from an array and assign settings to unit i.e. internet/web/web
autogprs = [
['23433', 'orangeinternet', '', ''],
['23434', 'orangeinternet', '', ''],
['23415', 'internet', 'web', 'web'],
['23402', 'mobile.o2.co.uk', 'mobileweb', 'password'],
['23410', 'mobile.o2.co.uk', 'mobileweb', 'password'],
['23411', 'mobile.o2.co.uk', 'mobileweb', 'password'],
['23430', 'general.t-mobile.uk', 'user', 'wap'],
['23431', 'goto.virginmobile.uk', 'user', ''],
['23432', 'goto.virginmobile.uk', 'user', ''],
['23420', 'three.co.uk', 'guest', 'guest'],
['64804', 'econet.net', '', ''], ]

6. Network Keep Alive
All cellular network SIM’s require additional GSM processing to keep registered on the network
All cellular network SIM’s require additional GPRS processing to remain activated and functional

7. Operating Mode (Client)
Client Mode (Using dynamic or fixed IP address SIM card)
Device initiates a remote TCP/IP connection to a listening server
Device connects on a specific programmed port
Device can be programmed to ‘maintain’ the TCP connection or to only connect when data is ready to be sent
Once the connection has been established the devices RS232 serial port is connected directly to listening server
The server can immediately process received information and post information back to the end device
Either the client or the server can initiate a disconnect
Device is immediately ready to reconnect to listening server

8. Client Mode
The Linkconnect (LC) modem is set up using a standard sim card. The LC is set up to point at the servers ip address and port. When the vending machine sells a mars bar it sends out a string over the RS232 port ‘1 mars bar sold’. The LC modem sends this string to the server where it is manipulated and used.
In this scenario the vending machine controls when the data is sent.
The server can also send messages back to the LC modem and request data, the server could send ‘How many mars bars are left?’. The modem would pass the string to the vending machine (the intelligence) and expect the vending machine to send a string in response.
The LC modem provides a ‘pipe line’ for data and creates a RS232 tunnel across the mobile network, it does not contain any intelligence and cannot respond to commands. This can only be used for one modem pointing at the servers IP address, as the LC modem doesn’t have a specific ip.

9. Operating Mode (Server)
Server Mode (Using a fixed IP address SIM card)
Device initiates a listening TCP/IP socket
Device listens on a specific programmed port
Device connects immediately to incoming socket request
Once the connection has been established the devices RS232 serial port is connected directly to connecting server
The server can immediately post information to the end device and process received information
Either the client or the server can initiate a disconnect
Device is immediately ready to reconnect to another connecting server

10. Server Mode
Fixed
IP Sim
The Linkconnect (LC) modems all have fixed IP Sim cards and are configured in server mode. The server sends strings of commands to the LC modems. The LC modem passes this string to the currently connected vending machine over the RS232 line, the vending machine interprets the string and sends a response over the RS232 line. The LC modem see’s the string and sends it back to the server.
The currently connected Vending machine can also initiate the sending of data.
The server is able to locate each modem because it has a fixed IP sim.

11. Questions
The remote connection is generally battery powered. Is there a method where the current consumption can be reduced? i.e reduce the frequency the modem polls for an available network connection etc. There isn't a low power mode as such, you can control how frequently the data is sent via the control device. LC will send whatever it sees on the RS232. So it is up to the user what appears on the RS232 port. Can the real-time connection be established from a remote source, rather than the user interface ? (i.e via an input to the modem). The user interface is only used for initial set up. The LC will maintain a connection and only send data when pushed or asked. As the modem has a prewritten driver for real-time data functionality. Can further code be added to the modem ? i.e establish a connection based on an alarm event to an input to the modem No the modem is like a pipe, once in place it is there to provide a route for data, the modem maintains this route. No other code can be added, in a way the modem is a ‘dumb’ modem. But because the pipe is already in place you can tell your pic that upon the alarm being triggered to send data. Is there a DLL style file to integrate the modem ‘user’ functionality directly into our own user interface software, rather than having to run two separate pieces of software ? No there isn’t. What is the maximum data rate and fix rates available ? i.e etc Will the connection cope with short pauses between sending packet of data or will there be pauses within the transmission ? The connection is constant, you choose when to send data. (whatever appears on the RS232 will be sent).