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[AT Commands] [Result Codes] [S Register Descriptions] |
Refer to your software documentation for instructions on using your software to dial numbers and answer calls.
Using the Dial Command
Your modem dials phone numbers when you give it the dial command (ATD) and a phone number, either alone or with dial modifiers.
The phone number must be an ASCII string containing the characters Ø through 9 (for pulse dial lines) or those numbers and A, B, C, D, #, and * (for touch-tone dial lines). The number cannot exceed the size of command buffer (54 characters excluding AT prefix, spaces, carriage return control character, and line feed control character).
The modem uses the dial command modifiers (listed below) in the order it encounters them on the command line, from left to right.
| P | pulse dial |
| L | re-dial the last number |
| T | touch-tone dial |
| W | wait for dial tone before processing the next character in the dial string (useful for PBX phone systems) |
| , | pause before processing the next character in dial string |
| ! | hook flash (go on-hook for 700 ms.) |
| ; | return to command state after dialing (must be last character in the command line) |
| ^ | enables calling tone, applicable to current dial attempt only |
| @ | wait for 5 seconds of silence before continuing |
To aid readability, spaces, hyphens, and parentheses can be added to the dial command line without affecting its function.
In the following example, your modem goes off-hook, waits for a dial tone, and then touch-tone dials the number 1 (405) 555-9624.
ATDT 1 (405) 555-9624 [CR]
If your modem does not receive a valid carrier from the remote modem within 50 seconds (the default value of register S7), your modem hangs up and sends the NO CARRIER result code. If the modem does receive a valid carrier within the time allowed, it will send a CONNECT XXXX message indicating the connection rate.
Automatic Pulse Dialing If Telephone System Does Not Support Touch Tones
If your local telephone system does not support touch-tone dialing, the way your modem acts depends on how it is configured.
If your dial string includes the P dial command modifier OR you have previously issued the P command, the modem will pulse dial.
If your dial string includes the T dial command modifier OR you have previously issued the T command, the modem will tone dial.
If your dial string does not include a P or T dial command modifier AND you have previously issued the T command, the modem acts in a way that can sometimes cause problems with PBX systems. For example, systems where a 9 is dialed to get a dial tone outside a company's in-house phone system. If you experience problems you think might be related to this, simply try an ATDT dial string. If that doesn't work, try an ATDP dial string instead. This should give you a dial string that works.
NOTE: Pulse dialing is not supported in some countries.
Answering Calls
The modem provides two ways to answer calls:
ATSØ=2 [CR]
If you set the modem to auto answer and your modem shares a line with a telephone, the modem may answer calls before you can intercept it. Be careful with auto answer if you do not have a dedicated modem phone line. By default, auto answer is disabled.
If you plan to use your modem to run a Bulletin Board System (BBS), the BBS software should automatically configure it for auto answer operation. If you think that you need to change it, refer to your BBS software manual or contact the BBS software publisher for details on how your modem should be set.