Black Box MD1276A, User Manual

Page: 65 / 289

AT Commands
Page 65
Direct Dialling
Direct dialling refers to your modem
’ s ability to dial a stored phone number when the DTR
signal of your computer is raised. This form of dialling is particularly suited to synchronous
computers and is referred in other parts of this guide as
‘ DTR Dialling ’ .
+ The &M command (used to select various methods of DTR dialling in AT command mode)
has no effect when the mode is operating in V.25bis command mode.
To select direct dialling:
•
Type: AT#D1 <E>
When DTR next goes from low to high, the modem will dial the stored phone number zero.
Please note, some dial modifiers supported in V.25bis command mode are different to those
supported in AT command mode and, thus, will be ignored by the modem if they are not
appropriate for the selected command mode. Refer to the previous section,
‘ Stored Number
Dialling
’ , for more information about storing phone numbers in your modem; refer to the
Command Descriptions section of this guide for more information about the dial modifiers
supported in V.25bis mode.
+
Direct dialling is also supported in V.25bis dumb mode. If your modem supports
dumb mode, refer to the Dumb Mode Section.
Answering Calls
Your modem is pre-configured to automatically answer incoming calls. If you receive a call on
the phone line the modem is connected to, it will answer the call and attempt to connect to the
calling modem.
When V.25bis mode is selected, your modem will automatically answer incoming calls after one
ring
– the setting of S Register 0 is ignored when V.25bis mode is selected. The communications
standard used by the modem in its attempt to connect with a calling modem is determined the B
command.
If the phone does ring, the modem will issue an INC message to indicate an incoming call has
been detected and will wait the number of seconds defined by S Register 71. S Register 71 allows
you to ignore a call by issuing a DIC command before the number of seconds defined by S
Register 71 is reached.
Thus, if S Register 71 is set to 10, you have 10 seconds after a call is detected to issue a DIC
command; if you do not issue the DIC command within 10 seconds, your modem will attempt
to connect to the calling modem.