ADTRAN 3000 - Manual (Page 86)

Chapter 7. Installing an Analog Modem
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the Express Configuration program (Tray Tool Menu) or by using a
VT-100 terminal emulation package (such as HyperTerminal).
If you are connecting an external analog modem that has not been
used by a PC running Windows 95/98, you must configure it before
you can use it (see Configuring the External Analog Modem on page 7-4).
Configuring the External Analog Modem
To configure the external analog modem, set up the communications
software so it uses the same serial COM port to which the
Express 3000 is connected.
To install and use an external modem that does not support
230.4 kbps, set
DIP Switch 1 on the back panel of the Express 3000 to
ON (down) , thus limiting the DTE speed to 115.2 kbps. To re-enable the
230.4 kbps operation for ISDN connections, set DIP Switch 1 to the
OFF (up) position.
When using an external analog modem that does not support
230.4 kbps with applications that support Express 3000 operation at
230.4 kbps, attach the Express 3000 to the high-speed 16650 UART
COM port and connect the external analog modem to a separate COM
port. This setup allows the Express 3000 to operate at 230.4 kbps and
the external modem to operate at the reduced speed.
Setting the Carrier Detect Signal
Before enabling the modem using the Express Configuration pro-
gram, set the
Carrier Detect (CD) signal from the modem to Normal
(track CD signal). Use the AT command AT&C1 to do this. To enter AT
commands into the modem, open a VT-100 terminal emulation ses-
sion and enter the following (
<cr> indicates you should press the En-
ter key to insert a carriage return):