# FXT and Extension Card RS485 **URL:** \ **Category:** Legacy FX/FXT series\ **Created:** [March 27, 2012, 8:58am UTC](https://forum.sierrawireless.com/t/fxt-and-extension-card-rs485/5531 "2012-03-27T08:58:46Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![zhihuialcatel](https://avatars.discourse-cdn.com/v4/letter/z/a9a28c/32.png) [@zhihuialcatel](https://forum.sierrawireless.com/u/zhihuialcatel)\ **Post date:** [March 27, 2012, 8:58am UTC](https://forum.sierrawireless.com/t/fxt-and-extension-card-rs485/5531/1 "2012-03-27T08:58:46Z")
Hello, Recently, I’m using the Fastrack Xtend Programmable Extendable Modem and the Extension Card RS485 for programming. The idea is like that, firstly, connect the RS485 and an electrical sensor with MODBUS Protocol, and in the program, set the configurations like the “BaudRate”, “ByteSize”, “Parity”, “StopBits”, then send the data/address commands according to the MODBUS, and the object is to receive the responses of sensor. In fact, I have done something related in [VB.Net](http://VB.Net), using the MSComm Controle. But here, in the Developer Stduio, I didn’t find the related methods/examples to do it, so can anyone give me some ideas of the programming over the RS485, or just some example? Thank u very much for your help. ---
**Author:** ![lotam](https://avatars.discourse-cdn.com/v4/letter/l/958977/32.png) [@lotam](https://forum.sierrawireless.com/u/lotam)\ **Post date:** [April 12, 2012, 1:51am UTC](https://forum.sierrawireless.com/t/fxt-and-extension-card-rs485/5531/2 "2012-04-12T01:51:16Z")
Hi, I don’t have the extension card with me, but ordinary AT command to configure baud rate, parity, etc, is AT+IPR and AT+ICF. For detail please refer to AT command guide. Maybe this old thread can give you some idea? [url][https://forum.sierrawireless.com/t/rs485-settings/5460/1](https://forum.sierrawireless.com/t/rs485-settings/5460/1)] Hope this helps. L