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.

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.

Indeed. Michel.