[Asterisk-Users] Re: Shielding of T1/E1 cables WAS RE: Pinouts for T1/E1 crossover

[Andrew Kohlsmith]

On Monday 24 April 2006 11:42, Ken Godee wrote:
> cat5 is NOT T1 cable and if any telco/vendor tried
> to install it in my location I'd have them pull it and
> put in the proper cabling.

T1 cable is generally Cat3 is it not?  That's certainly how the old T1s loops 
were run between the CO and the business...  From the smartjacks I've seen 
shielded Cat3 but Cat3 nontheless.

> T1 cable is not just insulated cable, the cable pairs are
> separately insulated, not just for enviroment conditions but
> to prevent cross talk.

Insulation (especially such thin insulation) does not prevent crosstalk.  
Distance, shielding and tighter twists do.

> The only safe way to try to use cat5 cable as a T1 cable
> would be two runs of cat5, one for Tx and one for Rx.
> It is necessary for the Tx and Rx signals to be in separate sheaths to
> prevent cross talk interferance.

Unless you're going for some kind of distance record, standard Cat5 will work 
without any issue on any modern installation.  As I said, I'm pretty sure 
(not 100%, but close) that the T1 specification is only Cat3, since it's 
standard BellCore wire and they don't run your T1 loops (which aren't T1 
anymore, they're DS1 over HDSL or HDSL2) in special "high end" trunks.

-A.