AT command problem
Posts: n/a and it works fine for some 5 minutes or so and returns OK. after that it starts returning funny charracters. Character that looks like a small rectangle( some what like this []). I have tried this on wavecom and round solutions modems and its the same on both. any clues ? Cheeros Rishi  Responses to "AT command problem"
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Posts: n/a Re: AT command problem Will try once i reach my place...but is it possible for the modem tofunction correctly for a while and then all of a sudden start returning junk if it is in autoo-baud ? Cheeros Rishi
Posts: n/a Re: AT command problem Hi John,thanks for the help last time. The wavecom modem did not have GPRS stack enabled so i switched to a round solutions modem. I was able to send mail using AT command. Cheeros Rishi
Posts: n/a Re: AT command problem rishi.israni@gmail.com wrote:> Will try once i reach my place...but is it possible for the > modem to function correctly for a while and then all of a > sudden start returning junk if it is in autoo-baud ? It shouldn't be possible, but that doesn't mean it isn't happening  Another possibility is that you're running at a fixed rate and character framing, and have got Wavecom reset (AT+WRST) set to 5 minutes (undoing your configuration). John
Posts: n/a Re: AT command problem Hi,I am using a round solutions modem now. My wavecom has some issues. wanted to ask u something. When i send AT command to the modem using my program...what is the best way of reading the return buffer. I mean how do i know when to stop reading. \r\n does not work for all commands... i look for the expected return, lets say OK when i send an AT command via my program and then i ignore what is after that and i flush before every send to the modem. Any good modem programming articles that u can point me to ? Cheers Rishi
Posts: n/a Re: AT command problem rishi.israni@gmail.com wrote:> Hi, > I am using a round solutions modem now. My wavecom has > some issues. > wanted to ask u something. When i send AT command to the modem > using my program...what is the best way of reading the return > buffer. > > I mean how do i know when to stop reading. \r\n does not work > for all commands... > i look for the expected return, lets say OK when i send an AT > command via my program and then i ignore what is after that > and i flush before every send to the modem. The following works for me: I handle the reading of the buffer with a purpose-built subroutine. I pass it 2 (optional) parameters: the response-termination string I'm expecting (usually "\r\nOK\r\n"), and the number of seconds to wait for further input if I don't see that string. This means that I might get other responses as well (I also expect unsolicited responses like "+CREG:", "+CSQ:", "+CCED:" and "+CBM:"), and need to separate these outside of this subroutine. So I always check the buffer for every type of response that might be expected. If the response happens to be incomplete, I leave the incomplete part of the response string there so that the remainder of that response gets concatenated to it at the next call to the input subroutine. This input subroutine waits around for a half-second or so for further input in any case, and I find it works perfectly reliably. I hope that helps. > Any good modem programming articles that u can point me to ? http://www.programmersheaven.com/ is a good starting point. John
Posts: n/a Re: AT command problem setting the baud rate works....hey do u know how i can turn off the RING and other such disturbing unsolicited responses  cheers Rishi
Posts: n/a Re: AT command problem rishi.israni@gmail.com wrote:> setting the baud rate works.... > hey do u know how i can turn off the RING and other such > disturbing unsolicited responses I haven't tested it, but you could have a look at "AT+CMER" (perhaps "AT+CMER=0,0,0" might work, but you might lose output you need too). A better, more defensive programming approach is to deal with them. I keep the device output in a buffer string variable. I frequently search that string for all result code introducers that interest me, and process them in a logical, sensible order. Having dealt with one, I immediately destroy it (by overwriting a character, changing "+CBM:" to "+ BM:" for instance). At appropriate points, I shorten the string or clear it completely. For commands that don't produce a leading result code (like "AT+CGSN"), I temporarily turn command echo on, and take my cue from the echoed command instead. John
Posts: n/a Re: AT command problem Some hints on the Round Solutions modem www.roundsolutions.com you willfind on http://www.gsm-modem.de/gsm-modem-faq.html . Sending of emails is descripted on http://www.gsm-modem.de/smtp-gprs.html . Regards Meff
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