[72727] in North American Network Operators' Group
RE: T1 short-haul vs. long-haul - jack terminology
daemon@ATHENA.MIT.EDU (Michel Py)
Sat Jul 24 17:31:51 2004
Date: Sat, 24 Jul 2004 14:30:36 -0700
From: "Michel Py" <michel@arneill-py.sacramento.ca.us>
To: <frank@dticonsulting.com>, <nanog@merit.edu>
Errors-To: owner-nanog-outgoing@merit.edu
> frank@dticonsulting.com wrote:
> I've seen where STP (shielded twisted-pair cabling) purists have
> succeeded in having shielded cabling used, only to screw it up by
> mis-applying the necessary grounding connections causing more
> problems than they solved.=20
I have also seen funny issues with RJ48C or RJ48X UTP, where the 7-8
pair is used for grounding. Same as STP when the shielding and/or the
equipment are not properly grounded, it can be a lot of fun. Makes a
real good antenna, to begin with.
> At one point the vendor's rep pointed to the fine print in the
> operator's manual. It stipulated that the only cabling that would
> be supported between the gateway and the telco demarc was
> individually shielded twisted pairs. When it was discovered that
> the client had chosen to use UTP patch cords to extend their T1
> demarcs some fifteen or so feet, the vendor would not even begin
> to diagnose the problem further in depth until the client replaced
> those cables with shielded ones.
Which emphasizes the need of having the demarc extended to the same room
where the equipment is, as replacing fifteen footers is easy, when
replacing a 300-ft run over ten floors is another story.
> as much as it is the significance of abiding by vendor warranty
> conditions (if you've agreed to them initially, even tacitly, in
> your contracts and SLAs) when selecting a T1 cabling solution.=20
Indeed.
Michel.
