Jim - what does span and non-span mean? I know that in analog telephone, DC feed is across a twisted pair, and in ISDN, T1, they typically use phantom power across the center taps of tx, and rvc transformers which uses 2 twisted pair. Victor
At 01:01 PM 9/18/96 PDT, you wrote: > >Try section 7 of Bellcore GR-1089-CORE. It allows as much as 200 VDC from >tip or ring to ground provided that the current when measured tip to ground >or ring to ground does not exceed 10 mA (Class A3). In reality, vendors of >central office ISDN typically generate -48VDC 10-20 mA DC for non-span >powered circuits, and <-140VDC <135mA DC for span powered circuits. T1 can >typically be dry (no DC voltage), -48VDC, or -130/+130 VDC with respect to >ground (repeater powering). I am sure there are multiple other schemes, but >this is what I am familiar with. > >Jim > ---------- >From: treg-approval >To: treg >Subject: ISDN and T1 maximum voltage >Date: Wednesday, September 18, 1996 9:06AM > > > >Subject: ISDN and T1 maximum voltage > > >Hello fellow TREG'ers, > >One of my colleagues asked me the following questions and I was unable to >provide an answer. I >would welcome any help from some one who knows. > >The question is what is the maximum voltage and current I can expect >to get out of a T1 or ISDN line. > >I know the power isn't very high normally, but how much can the max be? >I couldn't find an upper limit. References to the correct standards >would be nice. > >Thanks, > > >Dan Teninty P.E. >Senior Design Engineer >Product Safety >[email protected] >FLUKE Corporation >Everett, Washington >(206) 356-6035 >(206) 356-6490 fax > > > > > > >
