Donald Ritchie wrote: > The thing I wonder about, that doc is like 15 years old, and while it > explains incoming CID > it said nothing about CID delivery on a "call waiting" call. > I wonder if anybody REALLY knows how this works ? >
cwcid- the co outbound audio path is opened, cwtone is sent followed by bell 202 equivalent data stream then the path restored. for regular cid, 1/2 second after end of first ring, co path opened, bell 202 data stream sent, path restored. the cid receiver is coupled to the co line with two 100k resistors in series with two .01mf caps. That circuit has REN = 0 and will easily withstand 90v ring voltage. the receiver will sync and receive the data steam after "hearing" the alternating 1/0 preamble tone pattern. the receive has no means of signaling or handshaking to the co line. the original receivers used the ring voltage cycle as a "wake-up" signal to save power. the new circuits are low power cmos and listen all the time. you can spoof caller-id by sending your "own" cid stream just after answer (overwrites prev display - still in mem though). you can send the tone anytime, but voice component tends to tear up fsk stream. Original co used relay to drop loop and add 202 modem, co had to be "conditioned" for insertion. the modems were shared common equipment and were only connected to a line for a little over 1 sec. most recent computer modems can receive cid by setting an "at" cmd like #CID=0 (thru 3) 1/2/3 is raw, ascii, formated. most still use the ring cycle to "pull" the dial pulse reed relay to connect the modem chip "playing" a bell 202 receiver. latest ones can do cwcid as well. Carl should be in here, he put in his time at a co ;-) [btw my fav was the MCXI lines!] i would wonder if pano has enough transmitters to send that much cid. the kxtd with a 171 only had 1 channel. not enough shared equipment. has it ever worked? (never touched a ta) go buy your own bellcore ;-) -l _________________________________________________________________ KX-T Mailing list --- http://kxthelp.com/ Subscription changes: http://kxthelp.com/mailman/listinfo/kxt
