Aastra OpenCom 510 User Guide - Page 156

Types of Point-to-Point Connections, 14.2.1 Direct Connection, L1 Type, L1 sync possible

Page 156 highlights

PBX Networking Types of Point-to-Point Connections If more than one port with the setting L1 Type = "Slave" is configured on an OpenCom 510 and the setting L1 sync possible has been activated, then one of the ports is automatically 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 S2M interface of the type MT+S2M11 is installed, it will be selected as the preferred clock source. Please note: Reciprocal or circular application of the L1 clock is not allowed. 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 temporarily. When applying the L1 clock of trunk lines, you can assume that the public network is "clock-aligned". So, in the above example, you can connect additional trunk lines to one of the PBXs. 14.2 Types of Point-to-Point Connections There are different types of connection available for an point-to-point connection between two PBXs, depending on the distance between them. 14.2.1 Direct Connection This type of ISDN point-to-point connection joins the two systems directly to each other using a crossover twisted-pair cable. An S0 connection can be used for distances up to 1,000 metres, while an S2M connection can 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. PBX 1 L1 master L2 master L3 master Direct connection PBX 2 L1 slave L2 slave L3 slave 154

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PBX Networking
Types of Point-to-Point Connections
154
If more than one port with the setting
L1 Type
= “Slave” is configured on an
OpenCom 510 and the setting
L1 sync possible
has been activated, then one of
the ports is automatically 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
2M
interface of the type MT+S2M1-
1 is installed, it will be selected as the preferred clock source.
Please note:
Reciprocal or circular application of the L1 clock is not al-
lowed.
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 temporarily.
When applying the L1 clock of trunk lines, you can assume that the public network
is “clock-aligned”. So, in the above example, you can connect additional trunk lines
to one of the PBXs.
14.2
Types of Point-to-Point Connections
There are different types of connection available for an point-to-point connection
between two PBXs, depending on the distance between them.
14.2.1
Direct Connection
This type of ISDN point-to-point connection joins the two systems directly to each
other using a crossover twisted-pair cable. An S
0
connection can be used for dis-
tances up to 1,000 metres, while an S
2M
connection can 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.
Direct connection
PBX 1
L1 master
L2 master
L3 master
PBX 2
L1 slave
L2 slave
L3 slave