Westermo MR Series - Manual (Page 165)

165 6622-3201
Web Interface and Command Line Reference Guide www.westermo.com
Confi gure > ISDN LAPB > LAPB n 4.52
LAPB (Link Access Procedure Balanced) is a standard subset of the High-Level Data Link Control
(HDLC) protocol. It is a bit-oriented, synchronous, link-layer protocol that provides data framing,
flow control and error detection and correction. LAPB is the link layer used by X.25 applications.
Using the Web Page(s):
The Configure > ISDN LAPB folder expands to list separate pages for the LAPB 0 and LAPB 1
instances that allow you to set the following parameters.
Layer 1 interface:
This parameter determines which physical interface is to be used for carrying LAPB data. This
can be set to either “ISDN” or “Port”. If “ISDN” is selected then LAPB data is carried over the
ISDN BRI physical interface. By selecting “Port”, LAPB data can be routed to either ASY 0 or
ASY 1 (operat ing in synchronous mode), as selected by the Sync Port parameter below.
To configure ASY 0 or ASY 1 for synchronous operation refer to the Configure > Sync Ports
page.
Sync port:
This parameter is only relevant if the Layer 1 interface option above has been set to “Port” (as
opposed to ISDN). It is used to select ASY0 or ASY1 as the layer 1 interface for LAPB data.
Answering:
If this parameter is set to “On”, the unit will answer incoming calls on the relevant LAPB ses-
sion. To prevent the unit from answering incoming calls on this LAPB session set the option to
“Off”.
DTE/DCE mode:
When this parameter is set to “DTE”, the unit will behave as Data Terminal Equipment with
respect to the ISDN network. This is the default value and should not be changed for normal
operation across the ISDN network. If your application involves using two units back-to-back,
one of the units should have the DTE/DCE mode value set to “DCE” so that it acts as Data
Communications Equipment.
MSN:
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 Answering “On” 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.
If Answering is “Off” this parameter is not used.
Sub-address:
This parameter provides the filter for the ISDN sub-addressing facility. It is blank by default
but when set to an appropriate value, with Answering enabled it will cause the unit to answer
incom ing ISDN calls only where the trailing digits of the sub address called match the Sub-
address value. For example, setting the Sub-address to 123 will prevent the unit from answering
any calls where the sub-address called does not end in 123.
If Answering is “Off” this parameter is not used.
CLI:
Calling Line Identification. The unit will only answer calls from numbers whose trailing digits
match what is entered in this field. The line the unit is connected to must have CLI enabled by
the tele coms provider, and the calling number cannot be withheld.