> Does anybody have the real story behind mixing different telco =
circuits
> on a dual-T1 PM3?
>=20
>=20
> I'm particularly interested in knowning if a PM3 can mix PRI and =
CT1, served
> from the same switch, on a single chassis? I'd like to be able =
to mix
> 64K ISDN and analog callers on one box, without having to order =
both circuits
> as PRI- the CT1-vs-PRI recurring cost is considerably different!
>=20
>=20
> Livingston has said that on the dual-T1 PM3, both circuits need =
to be
> served from the same telco central office because problems will =
occur if
> the clocks on the two circuits are not in sync. But I have read =
here that
> people have successfully used a dual-T1 PM3 with circuits from =
two distinct
> telephone _companies_.
>=20
> What's the real story?
Ahh, timing, one of my favorite topics. The PM3 *should* clock =
each T-1 off of the loop separately, but I don't know if they do. =
When AT&T ran everything they created a very stable and reliable =
clock source that was distributed throughout the network. Since =
the breakup, the baby bells have kept the same clock sources and 2 =
different switches should provide identical timing becuase they =
both reference the same clock. I don't know about the clock source =
of the MCI's, Sprint's and the MFS's of the world though. My guess =
would be they either use an internal clock or take clock from a =
tandem switch.=20
Please see above question that was not answered. The 2 T-1's in a =
PM3 should not be aware of the others clocks because each T-1 is =
taking clock off of it's own span coming into it.=20
Kyle Platts
CSS-Tech
!NTERPRISE Networking Services