Newsgroups: comp.dcom.telecom.tech
Subject: Re: T1 wiring
From: floyd@tanana.polarnet.com (Floyd Davidson)
Date: 1 Nov 97 03:27:55 GMT

In article <345e38a9.15294912@news.hal-pc.org>,  <wdg@[204.52.135.1]> wrote:
>In article <19971031021001.VAA19215@ladder02.news.aol.com>
>mrpibb1997@aol.com (MrPibb1997) writes:
>
>>Tx and Rx need to be at least 100 pair apart for T-1. Save yourself alot of
>> hassle and run some new cable.
>
>Bzzzzt!!
>
>Merely 1 binder separation (25-pair) in the feeder cable is standard
>practice. For individual T1 *distribution* between the telco frame and the
>drop equipment you can use standard garden variety Cat-5 and put both the
>tx and rx pairs in the same cable. If it's standard 4-pr Cat-5 cable and
>you're in a real hurry or on a tight budget you can even put 2 T1s on a
>single cat-5 (4pr) cable and it will work fine (tho I don't personally
>recommend doubling up like this).  Remember folks, Category Five cable is
>rated to 100 Mhz with only slight deratings all the way to 300 Mhz.  A T1
>circuit only operates at 1.5 Mhz. You *do not* need shielded cable for
>horizontal T1 distribution. Cat-5 will do it with elegance, grace and very
>minimal cost.

A DS-1 interface operates at 778 Khz, not 1.544Mhz.  However,
cabling between points that are not in the same equipment row
should use shielded cable; while cabling between racks in the
same row can use unshielded cable.

The shielding is as much to avoid interfering with other
circuits as it is to protect the DS-1 signal itself.  Generally
there seems to be no end to what one can get away with when
there is only one circuit!  The problems come when that one
circuit later becomes, to everyones amazement, the first of many
many circuits.  That is when someone says "Who was the idiot
that put this one in?", and nobody answers...

  Floyd

--
Floyd L. Davidson   <floyd@tanana.polarnet.com>   Salcha, Alaska