User`s guide

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N400 Counter x
This is the standard LAPB retry counter. The default value is 3 and it should not normally be
necessary to change this.
RR Timer x milliseconds
This is a standard LAPB “Receiver Ready” timer. The default value is 10,000ms (10 seconds)
and it should not normally be necessary to change this.
T1 Timer x milliseconds
This is a standard LAPB timer. The default value is 1000 milliseconds (1 second) and under
normal circumstances, it should not be necessary to change it.
T200 Timer x milliseconds
This is the standard LAPB re-transmit timer. The default value is 1000 milliseconds (1
second) and under normal circumstances, it should not be necessary to change it.
X.25 Window Size
This parameter is used to set the X.25 window size. The value range is from 1 to 7 with the
default being 7.
Disconnect link if there has been no X.25 activity for x seconds
This parameter may be used to specify the length of time (in seconds) before the link is
disconnected if there has been no X.25 activity. If this parameter is zero or not specified,
then the inactivity timer is disabled.
Disconnect link if there has been no activity for x seconds
This parameter may be used to specify the length of time (in seconds) before the link is
disconnected if there has been no activity. If this parameter is zero or not specified, then
the inactivity timer is disabled. It is useful to set this to a short period of time (say 120
seconds) when a LAPB instance is being used over ISDN for example with TPAD. Should the
POS device fail to instruct TPAD to hang up then this timer can be used as a backup hang-
up timer thus saving ISDN call charges. When LAPB is being used on a synchronous port,
this parameter should normally be set to 0.
Send X.25 Restart packet on receipt of SABM frame
This parameter can be set to “No” or “Immediate”. When set to “Immediate”, the LAPB
instance will send an X.25 restart packet immediately on receipt of an SABM (Set
Asynchronous Balanced Mode) frame. If the parameter is set to “No”, then no X.25 restart is
sent.
ISDN Parameters
Configuration – Network > Legacy Protocol > X.25> LAPB> LAPN n> ISDN
Parameters
Allow this unit to answer calls
When this parameter is enabled this instance of LAPB will answer incoming ISDN calls.
Only accept calls from calling number ending with
This parameter provides the filter for the ISDN Multiple Subscriber Numbering facility. It is
blank by default but when set to an appropriate value with “Allow this unit to answer calls”
enabled it will cause the unit to answer incoming calls only to ISDN numbers where the
trailing digits match the MSN value. For example, setting the MSN parameter to 123 will
prevent the unit from answering any calls to numbers that do not end in 123.
Only accept calls with sub-address ending with
This parameter provides the filter for the ISDN sub-addressing facility. It is blank by default
but when set to an appropriate value, with “Allow this unit to answer calls” enabled it will