Types Of Point-To-Point; Connection - DETEWE OpenCom 510 User Manual

protocol master sets the clock for
layer 1, and the L1 protocol slave
adopts (synchronises to) this clock.
When planning a PBX networking
scheme, you must make sure that
the L1 clock propagates from a mas-
ter via a number of PBXs.
Network
operator
Example: propagation of the L1 clock
If more than one port with the set-
ting L1 Type = "Slave" is configured
on an OpenCom 510 and the setting
L1 sync possible has been activated,
then one of the ports is automati-
cally defined as the L1 clock source.
The OpenCom 510 will automatically
switch the clock source to another
port configured as an L1 clock source
(if a line fails, for example).
LED 3 (top right) of an interface card
will light up if one of the interfaces
on the card has been selected as a
clock source. If an S
the type MS+S2M1-1 is installed, it
will be selected as the preferred
clock source.
Please note: Reciprocal or circu-
lar application of the L1 clock is not
allowed.
104
PBX Networking
PBX1 PBX 3
M S M S
M
S
Trunk line
Point-to-point
PBX 2
M

connection

interface of
2M
Example: In the above case you
could reverse the L1 slave/master
setting for the connection between
PBX 1 and PBX 3. However, if you
then activate the setting
L1 sync possible for the port of PBX
1, this may cause parts of the PBX
network to stop functioning tempo-
rarily.
When applying the L1 clock of trunk
lines, you can assume that the public
S
network is "clock-aligned". So, in the
above example, you can connect ad-
ditional trunk lines to one of the
PBXs.

Types of Point-to-Point

Connection
There are different types of connec-
tion available for an ISDN point-to-
point connection between two PBXs,
depending on the distance between
them.
Direct Connection
This type of point-to-point connec-
tion joins the two systems directly to
each other using a crossover
twisted-pair cable. An S
can be used for distances up to 1,000
metres, while an S
span up to 250 meters. Normally one
PBX is the protocol master for all
three layers, and the other PBX is the
protocol slave for all three layers.
connection
0
connection can
2M
PBX Networking