Campus-REX RS Interface Card User Manual

Set Up the Campus-REX System
Campus-REX RS Interface Card User Manual 3-29
SET THE TIMING SOURCE
The Timing Source option determines the source of circuit timing on the
HDSL link. There are two settings for the Timing Source option:
• Internal: Sets the Campus unit to take its timing from an internal
oscillator. This is the default setting.
• HDSL: Sets the Campus unit to take its timing from the HDSL link.
The proper setting of the Timing Source option depends upon the interface
card of the remote Campus unit:
• If the Campus-REX is connected to a Campus unit with another
Campus-REX RS Interface Card, leave the Timing Source option set to
Internal. The Campus system will not operate properly if both units are
set to HDSL.
• If the Campus-REX is connected to a Campus unit with a synchronous
interface card, such as a Fractional V.35 card, the timing source depends
on the setting of the Primary Timing Source option of the remote unit:
– Set the Timing Source to HDSL if the remote unit is set to Internal
or Port.
– Set the Timing Source to Internal if the remote unit is set to HDSL.
See the Campus-RS Fractional Interface Card User Manual for
information on the Primary Timing Source option.
• If the Campus-REX is connected to a Campus unit with a Campus
CSU/DS-1 or CSU/DSX-1 interface card, leave the Timing Source
option set to Internal.
CAD1069i5.book Page 29 Thursday, May 30, 2002 7:32 AM