User`s guide

114
Advanced
Configuration – Network > Interfaces > Serial> Serial Port n> Advanced
The configuration parameters in this section are changed less frequently than those in the
basic section and so are given a separate page in order to reduce screen clutter.
Answer V.120 calls after n rings (0 = Don’t answer)
This parameter controls the answering of incoming V.120 calls. When set to zero, V.120
answering is disabled, otherwise V.120 answering is enabled on this interface. Enter the
number of rings to wait before answering the call into this text box. This is equivalent to
setting the value of the “S0” register for the associated serial port.
DCD
This drop-down selection box selects how the Data Carrier Detect (DCD) signal is controlled.
The available options are:
Auto
On
Off
Pulse Low.
Selecting “Auto” configures the router so that it will only assert the DCD line when an ISDN
connection has been established (this is equivalent to “AT&C1”).
Selecting “On” configures the router such that the DCD line is always asserted when the
router is powered-up (this is equivalent to “AT&C0”).
Selecting “Off” configures the router such that the DCD line is normally asserted but is de-
asserted for the time period specified by the “S10” register after a call is disconnected (this
is equivalent to “AT&C2”).
DTR Control
This drop-down selection box controls how the router responds to the DTR signal. The
available options are:
• None
• Drop call
• Drop line and call
• Drop call on transition
• Drop line & call on transition.
Selecting “None” configures the router to ignore the DTR signal (this is equivalent to
“AT&D0”).
Selecting “Drop call” configures the router to disconnect the current call and return to AT
command mode when the DTR signal from the attached terminal (DTE) is de-asserted (this
is equivalent to “AT&D1”).
Selecting “Drop line and call” configures the router to disconnect the current call, drop the
line and return to AT command mode when the DTR signal is de-asserted (this is equivalent
to “AT&D2”).
DTR de-bounce time s x 20 milliseconds
This parameter determines the length of time (in multiples of 20ms) for which the DTR
signal must be de-asserted before the router acts on any options that are set to trigger on
loss of this signal. Enter the desired multiple into the text box. Increasing this value makes
the router less sensitive to “bouncing” of the DTR signal. Conversely, decreasing this value
makes the router more sensitive. The default of 100ms (5 times 20ms) is a reasonable
value.
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