Bay Networks 3395A, Руководство по настройке

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Modem and Flow Control Operation
A-2 893-826-A
Figure A-1. State diagram for dial-in modems that support RNG
The following list describes the sequence of signals for this application:
• Server asserts DTR upon seeing RNG.
• Server deasserts DTR if DCD is not asserted within 60 seconds of the
assertion of DTR.
• Server permits data flow without waiting for the modem connected to the
server port to assert the DCD signal (you can autobaud the port by
pressing the RETURN key to select the port speed, when the PORT
AUTOBAUD characteristic is set to ENABLED). However, the DCD
signal must be asserted within 15 seconds after you start autobauding the
port or logging in, or the session will be disconnected.
• Server deasserts DTR if user does not log on within 120 seconds after the
modem has asserted DCD.
• Server performs the disconnect sequence if DCD is deasserted for more
than the period of time specified by the DCD TIMEOUT characteristic
(default is 2 seconds).
• Server deasserts DTR if the user logs out of the port.
Dial-in Modems that Do Not Support RNG
This configuration is the standard for dial-in lines that do not support the RNG
modem control signal. The port asserts the DTR modem control signal by
default.
Figure A-2 shows the modem states that the port enters as it observes
or asserts various modem signals (in the diagram, circled items indicate port
states, arrows indicate activity).
No data,
no DCD
observed
for 60s
RI
observed
Port not logged
in within 120s
Port logged in
DCD not
observed
within 15s
DCD
observed
within 15s
Receive
data, no
DCD
Observe
DCD
high
Port
logged
out
DCD not
observed
for timeout
period
Deassert
DTR
Assert
DTR
Wait for
login
Wait 15s
for DCD
Run
Start
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