0 Replies Latest reply: Apr 24, 2013 12:58 PM by Carlos Palma RSS

Wavecom modem resets after receiving command


Greetings, I have been using the following sequence of AT commands to establish a GPRS communication

using Sierra Wireless Q2687 modem






AT+WIPBR=2,6,11,"APN name"




**some data**




It has worked so far when connecting the modem and a PC, but a serious problem arises when trying to use a microcontroller,

after extensive testing I have found that upon receiving AT+WIPDATA=2,1,1 the modem resets. So far I have read on some

forums that it is possible for a modem to reset when the current required for transmission is not supplied or the voltage drops

to less than 3.5 volts. My question is, why does it work with a PC but not with the microcontroller? I haven't changed the power

supply that came with the modem. I have also noticed that the microcontroller heats during the communication, but it still works

sending data through the serial port. I use a null modem cable to connect the microcontroller and the modem, which means pins

4,6,1 are short-circuited , as well as pins 7 and 8 in a DB9 connector.Tx and Rx are crossed and GND is common. When

monitoring the arrival of data, the server acknowledges a client (that means the socket was created, right?) but unfortunately

no actual data arrives.

Any help will be greatly appreciated.