Nortel Circuit Card Installation Manual page 470

Page 470 of 906
Table 158
Connect and disconnect protocol (Part 10 of 12)
Mode of
operation Interface application
Mode 12 Terminal access for call
origination and answering
553-3001-211 Standard 3.00
NT7D16 Data Access card
August 2005
Comments
Terminal answering an incoming data call:
DAC drives DSR, DCD, and CTS ON in the idle
state.
Local DM user dials the access number to initiate
the connection.
DAC responds by driving RI ON for 2 seconds and
OFF for 4 seconds, until the terminal answers by
turning DTR ON (if the terminal always drive DTR
ON, the DAC immediately answers the call
without driving RI ON).
When terminal receives RI ON, it should respond
by turning DTR ON.
DAC answers when DTR goes ON and the local
DM user is now transparently linked to the
terminal.
Terminal originating an outgoing data call:
DAC drives DSR, DCD, and CTS ON in the idle
state.
Terminal turns DTR ON to initiate the connection.
DAC prepares to receive <CR> for autobaud.
Terminal sends <CR> followed by other
commands for establishing a data call (the DAC
echoes all commands).
Call disconnection (DAC):
If the local DM user releases the call, the DAC
turns DSR, DCD, and CTS OFF for 0.2 second
and then ON.