hello,
I hope repeating the same question with some different matter will not be removed from this forum.
Iam looking for discussion forums specially for telephony , PBX etc... can any one suggest any web link for this.

Also if some one can please suggest their veiw on my question i will be thankful.

Let say that i have connected 3 Telephone Sets no ringer circuit only 470 Ohms Resistor and a 9 Volts Dc Supply so that conversation can take place. no ringer , no tone etc..

Now i let say that one telephone set is the Master Set and the other two are slave.

From the Master Set when ever I dial digit "1" it get connected to one of the slave set , only connection nothing else...and when i dial "2" it connects with 2nd slave set.

Iam not using DTMF i.e. TONE set as for that i must have a DTMF decorder..iam using the old Pulse Dialing telephone sets

And at this stage only call is made from Master Set not from slave but the thing to note is that if iam talking to slave telephone set no.1 then slave no.2 should not hear any thing similar for slave no.2.

0,1,2 is the numbering of telephone sets

0 = Master telephone set, this can dail to any slave set by dailing "1" and "2" and when talking to one slave set the other should not listen..dailing the number "1" or "2" only connects the telephone sets no ringing no tone etc..

so what components i need. If 8051 then how to use that.