[VoiceOps] Adtran TA900 timing problems

Jay Hennigan jay at west.net
Mon Nov 4 16:14:53 EST 2013

On 11/4/13 9:41 AM, Matt Yaklin wrote:
> I forgot to mention that the cisco T1s on the DS3 use line
> timing in my setup. So line and line on both sides. The T1
> and the Adtran.

Don't do that then.  :-)

Every T1 span must have exactly one source of clocking.

My recommendation is to configure the T3 controller on the 7206VXR to
internal clocking on all of its T1s, and clock the Adtrans from T1 0/1

If both sides are set to internal, you'll get clock slips as the
oscillators drift slightly with respect to each other.

If both sides are set to line, then there's no reference clock.  The
line will probably sync up initially as the free-running T1 will be
close enough to sync.  Over time the frequency will drift up or down
until one side can no longer sync.  In some cases they'll recover on
their own, and in others you need to shut/no shut or otherwise force a

So, don't do that.

Jay Hennigan - CCIE #7880 - Network Engineering - jay at impulse.net
Impulse Internet Service  -  http://www.impulse.net/
Your local telephone and internet company - 805 884-6323 - WB6RDV

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