Mode 0 – Nortel Networks Circuit Card User Manual

Page 442

NT7D16 Data Access card

553-3001-211 Standard 3.00 August 2005

Mode 0

This mode should be selected when the DAC is connected to a modem, except
Hayes-1200, for inbound and outbound modem pooling (see modes 2 and 3
for Hayes-1200 modem). The modem used should have the following
features:

Auto-answer capability This feature is required when the modem is used for
inbound modem pooling. It allows the modem to drive the RI lead ON when
ringing is present at its tip and ring. In addition, the modem should
auto-answer after the first ringing cycle if the DTR lead is ON (most modems
support this feature).

Dynamic control of DCD This feature must be supported by all modems to
be connected to the DAC. It allows the modem to drive the DCD lead ON
when the carrier is detected and OFF when the carrier is absent (most modems
support this feature).

Figure 89
DAC to modem connectivity

pin 2
pin 3
pin 5
pin 6
pin 7
pin 8
pin 20
pin 22

TX
RX
CTS
DSR
GND
DCD
DTR
RI

DAC (DTE)

Modem (DCE)

(not required)

RS- 232 leads

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553-5215