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-48 volts

Posted: 27 Apr 2011 14:05
by letacla.alcatel
Hi,

Any one can breifly explain that "Why all the telecom equipments using -48dc volts?"

here..some reason
1.To prevent wire corrosion
2.due to the telephones sets
3.world wide Telephone operating volts-48
4.??????????

Re: -48 volts

Posted: 28 Apr 2011 03:12
by vad
Why all?
In many places (especially for old equipment) used "-60V".
For mobile equipment or small PBX (with short line) used "-24V".

Re: -48 volts

Posted: 28 Apr 2011 04:14
by letacla.alcatel
In general case.... mostly PBX operating volts -48..why..? is there any reason..?

Alcatel,OTN's, Mux's, Nortel, Siemens, Erricson...and so on.....

Re: -48 volts

Posted: 28 Apr 2011 06:16
by Konstantinos.E
hi

i think is because of the electronic equipment.maybe most of electronic parts for pbx's works more efficient under this voltage.

Re: -48 volts

Posted: 03 May 2011 04:02
by letacla.alcatel
hi

I know DC works more efficient......The Question is why -48V

{|48v|}....???????{|-_-|}........!!!!

Re: -48 volts

Posted: 03 May 2011 05:06
by vad
I think - for battery (from chemical point) was chosed 12V.
After, different system (with battery backup power) use 12, 24, 36, 48, 60 V power sources.
12 auto, very small PBX (Alcatel 4200 f.e. - 12 V for digital set and 48 for analog).
24 some auto, small PBX (Panasonic)
48 many telecom equipment.
64 old telecom equipment.

Re: -48 volts

Posted: 03 May 2011 06:26
by Konstantinos.E
.