Red Wave Radio

I know this is not directly on the subject, but I find that the
know-how is here.

Is there a web site which describes technically how caller identification
takes place during the ringing phase of a telephone call?

Not sure where to find the info on that but will equate maybe some relation
to Enhanced 911.  When someone dials 911 in a service area with enhanced
capability, the phone company receives the call and the computers recognize
where the call is coming from and when the call is routed to the appropriate
phone the call ID info is also transmitted.  So when the phone starts
ringing the call ID info is also present to be read.  Basically when the
phone starts to ring that electronic info is at the phone that is being
called.  This all occurs in just a couple of seconds................

According to the information in the data catalog that came along with
one of the decoder chips, the data is sent using 1200 baud tones (old
standard like we use for 1200 packet) between the phone rings. I believe
that it was sent ascii, but not certain on that point.

73's de W6QS - Don Labriola

why dont you try posting your inquiry on one of the telephony newsgroups?  i am
sure someone there will have the technical answer that you want.

regards

tim white

Email me if you cant find it, I ran the ad CALLER ID DEMYSTIFIED in nuts and
volts magazine 1996-1997, I give the byte by byte data stream that is sent . It
still costs 15.00

Kip

The CID signal is modulated in Bell 202 format (1200 Baud).  The Caller ID
data is sent between the first and second ring signal.

The ring signal is a 20Hz ring for 2 seconds.  0.5 seconds after the first
ring, the CID data is sent.
First 20 bytes of 01010101... for a pre-amble.  then 70ms of marks.
data is  then:  1 byte of message type, 1 byte message length, 1 byte
paramter type, calling name (in ASCII), 1 byte of parameter type, 1 byte of
paramter length, the 144 bits of month, day, hour, minute and the calling
number.  last byte is checksum.

You can visit the Motorola web site and request document DL136/D which is
the communications device data handbook.  Lookup IC  MC145447  which is a
CID decoder.  They also have a evaluation kit described, along with the CID
format

cheers

Quote:>I know this is not directly on the subject, but I find that the
>know-how is here.

>Is there a web site which describes technically how caller identification
>takes place during the ringing phase of a telephone call?

Quote:BIG BOPPER) writes:

Quote:>identification

Check out the web site for Circuit Cellar Magazine.  Some time ago they ran a
construction project for the normal caller ID and the call waiting ID too...

Quote:>Is there a web site which describes technically how caller identification
>takes place during the ringing phase of a telephone call?

it's the kind of thing that lancaster would have an article or 2 on.

also see comp.dcom.telecom and the telecom digest archives for leads.