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At 01:18 PM 9/18/96 -0700, you wrote: >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 >> >> >> >> >> >> >> > > > ___________ Jim Lambert ~~~~~~~~~~~
