Nortel Circuit Card Installation Manual page 450

Page 450 of 906
Figure 91
DAC to Gateway connectivity
DAC (DTE)
(not required)
(not required)
RS- 232 leads
Mode 4
553-3001-211 Standard 3.00
NT7D16 Data Access card
pin 2
pin 3
pin 5
pin 6
pin 7
pin 8
pin 20
pin 22
This mode should be selected when the DAC is connected to a gateway for
inbound and outbound operation. The characteristics of the gateways to be
used with this mode are:
Auto-answer capability This feature is required when the gateway is used
for inbound operation. It allows the gateway to drive the DCD lead ON when
the inbound data call is pending. In addition, the gateway should auto-answer
when the DTR lead is ON.
Dynamic control of DCD This feature must be supported by all gateways to
be connected to the DAC. It allows the gateway to drive the DCD lead ON
when the data call is established, and OFF when the data call is disconnected.
In the inbound operation, the DAC drives the DTR lead OFF until the
gateway drives the DCD lead ON. Then, the DAC drives DTR ON and makes
that unit busy for any outbound calls. After that, the user of the gateway may
enter the proper commands to establish a local data call to any DM.
August 2005
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Gateway (DCE)
TX
RX
CTS
DSR
GND
DCD
DTR
RI
553-5217