T1 AND E1 REMOTE ACCESS CONCENTRATORS
20
In certain unusual circumstances, you might need to connect an analog modem to the Concentrator’s console
port. (This type of connection would allow you to remotely administer the Concentrator by dialing in to the
modem.) To do this, you’ll need a special cable cross-pinned like this:
Signal
Concentrator
Modem
Signal
End
End
TD
1
2
TD
CD
2
DSR
3
8
CD
CTS
8
RD
4
3
RD
SGND
5
7
SGND
DTR
6
N/C
—
RTS
7
20
DTR
The modem
must
be configured as follows:
• 9600 bps, 8 data bits, 1 stop bit, no parity.
• Auto-answer enabled.
• Drop CD (Carrier Detect) when calls drop. (This setting helps prevent security breaches.)
• Ignore DTR and RTS.
NOTES
CD, DTR, and RTS settings may be changed by sending your modem “AT commands”
or, sometimes, by setting DIP switches. Refer to its manual.
When the modem is connected to the Concentrator and no call is up, none of the
Concentrator’s LNK and STS LEDs are lit. Once the call is connected, these LEDs
function the same way as if it were a local connection. Refer to the LEDs section of the
Concentrator’s HTML documentation.
