9.5 Text Messaging

Some phones and modems let you send a text message via Short Message Service (SMS) using AT commands. To find out whether your device supports this (nearly all GSM devices do), connect with Kermit, as shown in Example 9-1, and issue the query AT+CSMS=0 (the three columns indicate whether the device is capable of receiving messages, sending messages, or sending broadcast messages):

 AT+CSMS=0 +CSMS: 1,1,1     OK 

If your cell phone supports this capability, you can work with text messages using AT commands. You can list your text messages with AT+CMGL=4 (the 4 indicates all messages: use 0 for unread, 1 for read, 2 for unsent, and 3 for sent messages) and read a message with AT+CMGR= MESSAGE_NUMBER :

 AT+CMGL=4 +CMGL: 1,1,,28 07919170389103F2040B91XXXXXXXXXXF100013011320211500A0AD3771D7E9A83DEEE10 +CMGL: 2,1,,25 07919170389103F2040B91XXXXXXXXXXF100013011329135610A06C8F79D9C0F01     OK AT+CMGR=1 +CMGR: 1,,28 07919170389103F2040B91XXXXXXXXXXF100013011320211500A0AD3771D7E9A83DEEE10     OK 

However, you'll want to put the phone into text mode, so the responses that you receive are human-readable . Use AT+CMGF=1 for this, and try reading the message again:

 AT+CMGF=1 OK AT+CMGR=1 +CMGR: "REC READ","[phone]",,"03/11/23,20:11:05-20" Soup's on!     OK 

You can send a message with AT+CMGS= " PHONE_NUMBER " (but make sure you've set responses to be human-readable with AT+CMGF=1) . You'll be prompted for the message; type it and press Ctrl-Z when you are finished:

 AT+CMGF=1 OK AT+CMGS="  4015559000  " >  Hello, world!^Z  OK 

You can also use the gsmsendsms utility from gsmlib (http://www.pxh.de/fs/gsmlib/index.html) to send the message:

 bjepson@debian:~$  gsmsendsms -d /dev/ttyUSB0 4015559000 "Hello, World"