User`s guide

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Configuring X.21 on Older Models
Some older Sarian legacy units require an X.21 daughter card to be fitted to enable X.21
operation. There are two versions of the X.21 daughter card. One version is compatible with
GR2130, IR2140 and IR2420 routers, and one version is compatible with MW3520, MW3410
and VC5100 routers.
The X.21 daughter card compatible with GR2130, IR2140 and IR2420 routers has three
internal jumpers that determine the clock mode. By default, these are set so that the unit
acts as a clock sink. For correct X.21 operation the jumper settings must match the setting
of the Clock source parameter configured on the Configuration - Network > Interfaces >
Serial > Serial Port 0 > Sync Port 0 pages. To change this you will need to open the unit by
removing the four rubber feet and fixing screws. Having done this, carefully remove the
case lid and locate the X.21 adapter card (illustrated below):
The correct settings for clock source or clock sink operation for the X.21 daughter card
compatible with GR2130, IR2140 and IR2420 routers are shown below:
Having set the links correctly, reassemble the case ensuring that the lid is correctly
oriented.