About
Community
Bad Ideas
Drugs
Ego
Erotica
Fringe
Society
Technology
Phreak
Boxes, Old and New
Bugs and Taps
Cellular Phones
Introduction to Telecommunications
PBX's and Switches
Payphones
Phone Phun
VMB's, Pagers, E-Mail, and S&F Systems
register | bbs | search | rss | faq | about
meet up | add to del.icio.us | digg it

Caller ID coding info


NOTICE: TO ALL CONCERNED Certain text files and messages contained on this site deal with activities and devices which would be in violation of various Federal, State, and local laws if actually carried out or constructed. The webmasters of this site do not advocate the breaking of any law. Our text files and message bases are for informational purposes only. We recommend that you contact your local law enforcement officials before undertaking any project based upon any information obtained from this or any other web site. We do not guarantee that any of the information contained on this system is correct, workable, or factual. We are not responsible for, nor do we assume any liability for, damages resulting from the use of any information on this site.
From: [email protected] (Jeff Sicherman)
Newsgroups: comp.dcom.telecom
Subject: Caller-ID Specifications
Message-ID: <[email protected]>
Date: 1 Dec 91 01:30:39 GMT
Sender: [email protected]
Organization: Cal State Long Beach
Lines: 181

This is a copy of the data sheet picked up at the Rockwell
booth at the COMDEX show.

INTRODUCTION

Calling Number Delivery (CND), better known as Caller ID, is a
telephone service intended for residential and small business
customers. It allows the called Customer Premises Equipment (CPE) to
receive a calling party's directory number and the date and time of
the call during the first four second silent interval in the ringing
cycle. The customer must contact a Bellcore Client Company to
initiate CND service.

According to Pacific Bell representatives, the following states and
district currently support CND service: Delaware, District of
Columbia, Florida, Georgia, Idaho, Kentucky, Louisiana, Maine,
Maryland, Nebraska, Nevada, New Jersey, Oklahoma, Tennessee, Vermont,
Virginia, and West Virginia.

The following states are scheduled to support CND service by April,
1992: Alaska, Arizona, California, Colorado, Illinois, Indiana, Iowa,
Massachusetts, Mississippi, New Hampshire, New York, North Carolina,
North Dakota, Ohio, Oregon, Rhode Island, and South Carolina.

PARAMETERS

The data signalling interface has the following characteristics:
Link Type: 2-wire, simplex
Transmission Scheme: Analog, phase-coherent FSK
Logical 1 (mark) 1200 +/- 12 Hz
Logical 0 (space) 2200 +/- 22 Hz
Transmission Rate: 1200 bps
Transmission Level: 13.5 +/- dBm into 900 ohm load

(I have copied this data as presented. I believe the transmission
level is meant to be -13.5 dBm.)

PROTOCOL

The protocol uses 8-bit data words (bytes), each bounded by a start
bit and a stop bit. The CND message uses the Single Data Message
format shown below.

Channel Carrier Message Message Data Checksum
Seizure Signal Type Length Word(s) Word
Signal Word Word

CHANNEL SEIZURE SIGNAL

The channel seizure is 30 continuous bytes of 55h (01010101) providing
a detectable alternating function to the CPE (i.e. the modem data
pump).

CARRIER SIGNAL

The carrier signal consists of 130 +/- 25 mS of mark (1200 Hz) to
condition the receiver for data.

MESSAGE TYPE WORD

The message type word indicates the service and capability associated
with the data message. The message type word for CND is 04h
(00000100).

MESSAGE LENGTH WORD

The message length word specifies the total number of data words
to follow.

DATA WORDS

The data words are encoded in ASCII and represent the following
information:

o The first two words represent the month
o The next two words represent the day of the month
o The next two words represent the hour in local military time
o The next two words represent the minute after the hour
o The calling party's directory number is represented by the
remaining words in the data word field

If the calling party's directory number is not available to the
terminating central office, the data word field contains an ASCII "O".
If the calling party invokes the privacy capability, the data word
field contains an ASCII "P".

CHECKSUM WORD

The Checksum Word contains the twos complement of the modulo 256
sum of the other words in the data message (i.e., message type,
message length, and data words). The receiving equipment may
calculate the modulo 256 sum of the received words and add this
sum to the reveived checksum word. A result of zero generally
indicates that the message was correctly received. Message
retransmission is not supported.

EXAMPLE CND SINGLE DATA MESSAGE

An example of a received CND message, beginning with the message
type word, follows:

04 12 30 39 33 30 31 32 32 34 36 30 39 35 35 35 31 32 31 32 51

04h= Calling number delivery information code (message type word)
12h= 18 decimal; Number of data words (date,time, and directory
number words)
ASCII 30,39= 09; September
ASCII 33,30= 30; 30th day
ASCII 31,32= 12; 12:00 PM
ASCII 32,34= 24; 24 minutes (i.e., 12:24 PM)
ASCII 36,30,39,35,35,35,31,32,31,32= (609) 555-1212; calling
party's directory number
51h= Checksum Word

DATA ACCESS ARRANGEMENT (DAA) REQUIREMENTS

To receive CND information, the modem monitors the phone line between
the first and second ring bursts without causing the DAA to go off
hook in the conventional sense, which would inhibit the transmission
of CND by the local central office. A simple modification to an
existing DAA circuit easily accomplishes the task.

(I will mail the Rockwell data sheet, which includes the suggested
schematic diagram.)

MODEM REQUIREMENTS

Although the data signalling interface parameters match those of a
Bell 202 modem, the receiving CPE need not be a Bell 202 modem. A
V.23 1200 bps modem receiver may be used to demodulate the Bell 202
signal. The ring indicate bit (RI) may be used on a modem to indicate
when to monitor the phone line for CND information. After the RI bit
sets, indicating the first ring burst, the host waits for the RI bit
to reset. The host then configures the modem to monitor the phone
line for CND information.

(I'm skipping some Rockwell-specific information here.)

According to Bellcore specifications, CND signalling starts as early
as 300 mS after the first ring burst and ends at least 475 mS before
the second ring burst.

APPLICATIONS
Modem manufacturers will soon be implementing new modem features
based on CND information as this service becomes widely
available.

Once CND information is received the user may process the
information in a number of ways.

1. The date, time, and calling party's directory number can be
displayed.

2. Using a look-up table, the calling party's directory number
can be correlated with his or her name and the name
displayed.

3. CND information can also be used in additional ways such as
for:

a. Bulletin board applications
b. Black-listing applications
c. Keeping logs of system user calls, or
d. Implementing a telemarketing data base

REFERENCES
For more information on Calling Number Delivery (CND), refer to
Bellcore publications TR-TSY-000030 and TR-TSY-000031.

To obtain Bellcore documents contact:

Bellcore Customer Service
60 New England Avenue, Room 1B252
Piscataway, NJ 08834-4196
(201) 699-5800


[Moderator's Note: This article will also be filed in the Telecom
Archives (lcs.mit.edu) as a separate article in a couple days. PAT]
 
To the best of our knowledge, the text on this page may be freely reproduced and distributed.
If you have any questions about this, please check out our Copyright Policy.

 

totse.com certificate signatures
 
 
About | Advertise | Bad Ideas | Community | Contact Us | Copyright Policy | Drugs | Ego | Erotica
FAQ | Fringe | Link to totse.com | Search | Society | Submissions | Technology
Hot Topics
Php
Withstanding an EMP
Good computer destroyer?
Wow, I never thought the navy would be so obvious.
Alternatives Internets to HTTP
Anti-Virus
a way to monitor someones AIM conversation
VERY simple question: browser history
 
Sponsored Links
 
Ads presented by the
AdBrite Ad Network

 

TSHIRT HELL T-SHIRTS