AN010. Controlling the DS from the Serial Side

This Application Note is mainly aimed at manufacturers incorporating Tibbo modules into their products. It can also be used by anyone who can modify the behaviour of his serial device, and wishes to integrate it more tightly with a Device Server.

Device Servers can be made to act as 'modems'; Connections can be established and closed at will, by the serial device. You can also select the destination for the connection, and set other relevant parameters -- all from the serial side, and without writing to the EEPROM of the device.


This application note assumes prior knowledge in HyperTerminal. If you're not sure what HyperTerminal is, or how to use it to access a Device Server, please read AN008. Using HyperTerminal first and perform the exercises described in it, before moving on to study this present AN.

What You Need for Modem Commands to Work

To use modem commands, you need a serial device which can send them to the DS. This sounds elementary, but it is actually the first thing you should note. In effect, this means that your serial device would have to be 'tailored' for working with the DS. It would have to speak in a language the DS understands -- i.e, send the serial commands the DS could understand.

Since these commands are used specifically to communicate with Device Servers from Tibbo, standard serial devices don't come with the option to send them already built in. So, you have to be able to modify the firmware for your serial device to have it send these commands. Usually manufacturers can do this, but some serial devices are very flexible, and allow even an end user to perform such modifications (especially Linux-based devices, etc).

Topics In This Application Note

Specifically, we will take up the following topics:

Benefits of Modem Commands
Issuing Commands
Establishing a Connection
Terminating a Connection
Finding Out Connection Status (X)
Finding Out Connection Details (U)
Exiting Serial Programming Mode
Real-World Example