Is possible using programming of micrcontroller to sent CLI data so that eahc user can know from which extension they are receiving the call using normal CLI devices connected with their telephone sets in the similar way as we connect CLI with our external telephone receive line...

not for pbx only for extension to extension dailing...

Iam looking how data is can be sent from the controller ...

Like first the telephone set goes off hook from extension no. "11"

controller detect off-hook and sents dial tone using 555 timer IC.

when the user dial digit "12" using a pulse dialing setn controller check this number from uts memory list and sents ringing singal to "12" telephone set and at the same time ring back tone to the caller.

Now at this stage after 1 ringing bell user of telephone no. "12" should receive the extension number "11" on his CLI device.

is it possible using assembly coding if yes some hints needed..

or do i have use some chips...