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Egypt telephone interface

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newelltech

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telephone signal specifications in egypt

I am designing a telephone interface for use in Egypt.
Can anyone help me find the specifications for the telephone line?
My customer is measuring 50 volts on-hook and 7-9 volts off-hook which is standard. But when I ask him to measure the AC voltage, he claims there is 118 VAC when on-hook and 20 VAC when off-hook. Can this possibly be right? What is this AC voltage???
 

busy tone specification in egypt

newelltech said:
I am designing a telephone interface for use in Egypt.
Can anyone help me find the specifications for the telephone line?
My customer is measuring 50 volts on-hook and 7-9 volts off-hook which is standard. But when I ask him to measure the AC voltage, he claims there is 118 VAC when on-hook and 20 VAC when off-hook. Can this possibly be right? What is this AC voltage???
Click to expand...

ring tone is AC
tel. line is one tone (el harara) is AC
ring back is AC
busy tone is also AC
 

Do you mean Dial Tone for tel. line?
The measurements were taken after starting to dial - no ring tone, no dial tone, no ring back tone, no ringing.
Any ideas what this might be?
 

newelltech said:
Do you mean Dial Tone for tel. line?
The measurements were taken after starting to dial - no ring tone, no dial tone, no ring back tone, no ringing.
Any ideas what this might be?
Click to expand...

after calling a no. he must hear the ring back tone ....
 

I mean after dialing just the first digit of the number.
 

can you measure the freq. of this AC ??

many digital meter (fluke ....) can measure a low freq. AC????
 

Your coustomer is wrong. During On-Hook condition u never get A.C. voltage. On telephone line u will get AC voltage when RIng is coming.
 

Could simply be an antique instrument, that shows also DC voltage in AC range.
 

As I know a telephone line without any activity has a DC voltage (Value differs for countries) . Any activity (dilaing, ring tone,...) is sent using AC signals.
 

take for sure the answer of jatinbad
during the onhook period there is no ac excepting the eventual ringing signal
 

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