-48 volts

[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.??????????

[vad]

Why all?
In many places (especially for old equipment) used "-60V".
For mobile equipment or small PBX (with short line) used "-24V".

[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.....

[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.

[letacla.alcatel]

hi

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

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

[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.

[Konstantinos.E]

.