Modem Control

[Noggin]

I'm having problems getting my cellular modem to answer. I have DTR (active low) tied to ground. When the system is started, I wait about 8 seconds and then send "ATS0=2" to the modem to cause it to answer on the second ring.

If I dial to the modem, I see ring indicate (RI) flash twice, then nothing. About 10 to 15 seconds later my terminal program says "NO CARRIER".

Am I supposed to toggle a pin or something even if ATS0=2 is given to it?

I have over 240 pages of software documentation for commands and such, and HALF a page on hardware.

I can successfully dial FROM the modem to my computer though and can transfer data reliably for as long as I care. I just can't call from my computer to my modem.

 

[Clyd3]

How about you help me?

I'm sorry, because I'm a complete newbie, so I cant help you, but can you suggest to me where I can get the "documentation" you have on modem commands and alike...Please

 

[Noggin]

this is a cellular modem so many of the commands won't work, but most of the basic one will be the same. Let me see if the doumentation is availabe on their website...

I don't see the documents, but you can check for yourself at www.multitech.com

The booklet I have is called "interface guide" and there is also a developers guide that has things like the footprint of the device. Oh yeah, I have the embedded GSM SocketModem. If I knew where my CD was I'd just email the PDF to you.

 

[Noggin]

Occasionally when I dial from the modem to my computer I lose signal. I wonder if thats because my power supply just barely meets the requirements for the modem, but I'm also driving a MCU and a GPS with it (about 150 mA). If thats the case, then that may explain why it won't properly answer incoming calls.