Hi Jack, You are correct, -40 to 57.5 at the battery plant. The AT&T NEDs specification is the most conservative. You will find that they require you not operate below -39VDC (-40VDC at the battery plant). There is also some hysteresis built in to the "Turn Back On" threshold of -43V.
You may want to take a look at the transport requirements in GR499 and GR 513 have the Telcordia requirements and objectives for digital transport systems. Have a Great Day! Dave Spencer -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Tuesday, November 19, 2002 2:00 PM To: [email protected] Subject: RE: 48Vdc tolerance I have all of the checklists and the widest range I found was -40 to -57.5Vdc. One of the hardware designers here recalls a Bellcore spec that included a range to -36Vdc. I haven't found it yet. If I do, I'll post it. Thanks for all of your responses, they all support the -40Vdc limit (so far). Jack -----Original Message----- From: Joe Finlayson [mailto:[email protected]] Sent: Tuesday, November 19, 2002 4:28 PM To: '[email protected]' Subject: RE: 48Vdc tolerance Jack, -40VDC to -56.7VDC rings a bell. I believe I got the -40VDC (1 minute soak) as a worst case from the SBC TP76200MP document and the 56.7 is standard based on +5% of the -54VDC C.O. float voltage. I believe you'll also find the 56.7 value in SBC's doc as well. I can't say I can recall any other specs off the top of my head that go outside of these ranges, but someone else may be able to cite another standard. I shoot for -40 to -60. Thx, Joe -----Original Message----- From: [email protected] [mailto:[email protected]] Sent: Tuesday, November 19, 2002 2:41 PM To: [email protected] Subject: 48Vdc tolerance Has anybody any information on the required operating range for equipment with respect to -48Vdc power? I'm looking for Telcordia requirements outside of the NEBS requirements that apply. Thanks, Jack
