Re: Electricity and Telephone usage in Pakistan?
Wednesday, November 5th, 2008 at
6:10 pm
A.J asked:
In Pakistan there is a big problem of load shedding and the electricity board normally cut electricity supply up to 10 hours in some major cities BUT households without electricity still have an active telephone line?
HOW without electricity?
Tagged with: Electricity Supply • Major Cities • Pakistan
Filed under: Land Phones
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sussex electric
Traditionally, PSTN landline phones (public switched telephone network) supply the DC voltage and current necessary for a corded telephone to operate without any other power source. The current-limited voltage supplied by the telco phone line (typically -48 Vdc) is all your corded telephone needs to make and receive telephone calls. The phone service line is backed-up by large banks of batteries that are being charged all the time that normal AC power is available. When AC power is interrupted, the DC batteries will power the telephone lines by themselves until AC power is restored, or until the batteries go dead. It is also likely that the telco’s have emergency generators to temporarily charge the batteries during short periods of power outage.
Just remember, you phone will only work if it is a “corded” telephone. Corded telephones will operate directly off of the telco phone line. But, if you use “cordless” phones, the cordless phone Base unit requires power to operate. Thus, during power outage, the cordless phone base unit will not function.
This is why I also maintian a UPS power backup system for my cordless phones and computer. This way, I can still operate the equipment during short periods of power outage without disruption.