[comp.dcom.telecom] CLID Compatibility Question

winslade@zeus.unomaha.edu (JOHN WINSLADE) (01/19/91)

At a local sysops' gathering tonight, the subject of Caller*ID <tm>
came up and it was mentioned by one participant that he had heard that
the Class- Mate <tm> would not work in US West territory, supposedly
due to differences in the way US West sends the CLID data.

Class-Mate is a widget that connects between a CLID-equipped phone
line and a computer's line that converts the incoming CLID data to
serial data that may be captured by the computer.  It's is available
from Bell Atlantic and possibly other sources.

Is it >>REALLY<< the case that US West uses a different scheme for
CLID??  I am now using a CLID box that I got from Hello Direct -- the
same box that is sold to non-US West subscribers, as far as I know.
The box works fine here, and I know the same model CLID box works in
New Jersey as well.
 
Also, I had the impression that the Class-Mate was more or less a
passive device that demodulated the CLID data and converted it to
RS-232 compatible levels, and did not really do any heavy-duty data
conversion.  Am I correct in assuming this.  Thanks.
 

Good Day!       JSW


[Moderator's Note: Since an ultimate goal is to make Caller-ID
available to everyone on all calls throughout the USA I would think
the individual systems throughout the country are compatible.   PAT]

dave@westmark.westmark.com (Dave Levenson) (01/20/91)

In article <16200@accuvax.nwu.edu>, winslade@zeus.unomaha.edu (JOHN
WINSLADE) writes:

> Also, I had the impression that the Class-Mate was more or less a
> passive device that demodulated the CLID data and converted it to
> RS-232 compatible levels, and did not really do any heavy-duty data
> conversion.  Am I correct in assuming this.  Thanks.

The ClassMate appears to be a little more intelligent than that.  When
it is powered up, it outputs a four-line message in ASCII identifying
itself, giving its firmware copyright notice and version information.
It validates the checksum passed by the telco, but does not pass it
along to the RS-232 port.  It does pass a single character indicating
the validity of each message.

It appears to contain a modem (really, just a -dem) to demodulate the
incoming caller id information, a buffer memory for one message, and a
UART to talk to the RS-232 port.  There is probably also a
microprocessor that runs this stuff.  It most-likely consists of a
microcomputer -- one chip that contains ROM, RAM, and two serial
ports.  With such a device, one only needs the modem and the passive
components to drive the serial port at RS-232 levels.


Dave Levenson		Internet: dave@westmark.com
Westmark, Inc.		UUCP: {uunet | rutgers | att}!westmark!dave
Warren, NJ, USA		AT&T Mail: !westmark!dave
Voice: 908 647 0900	ax: 908 647 6857

oheare@uunet.uu.net (David O'Heare) (01/24/91)

In article <16200@accuvax.nwu.edu>, the Moderator notes:

> [Moderator's Note: Since an ultimate goal is to make Caller-ID
> available to everyone on all calls throughout the USA I would think
> the individual systems throughout the country are compatible.   PAT]

Well, the scheme used in Canada is explicitly NOT the same as that
used in the U.S., in spite of the close coupling of our phone systems.
The gadgets supplied by Bell Canada will understand the sceme used by
most, though not all, of the U.S. RBOCs. The gadgets supplied by most
U.S. RBOCs and third party vendors understand only a subset of the
data stream that Bell Canada puts out; usually just enough to get
confused.

On a similar note: does anybody out there know WHY Bell Canada chooses
to send the particular phone number that it does? I would have thought
that they'd send the pilot number of a hunt group, for example, rather
than the explicit number within the group. Any ideas?


Dave O'Heare    oheare@gandalf.ca    +1 613 723 6500