I believe each state decides what the rules are concerning availability
of CID blocking and what the costs will be.  Thats what all these
court cases have been about.

Not to worry about a "different" phone company not supporting blocking,
since I believe you local switch just does not generate the data
if the blocking is engaged on that call.  The "far" switch has nothing
to do with it.

By the way, if you're so paranoid you won't answer a call with "private",
then I probably don't care to talk to you.

Caller-Id Info Follows
-------------------------------------------------------------------------
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 4 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

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.

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.

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
	(908) 699-5800

==========================================================================
==========================================================================

Good morning!

I have been selling caller ID chips and data sheets for a few weeks
now. I will attach a copy of my flyer to the bottom of this note.
You might be interested in an offer I have made to the internet; send
me a SASE and I'll send you the data sheet. The data sheet for the CID
receiver I sell does include detaild of the data encoding. If you
have any other questions, feel free to drop me a note.

John

------------cut here %<--------------------------------------------------


Please feel free to copy this document and distribute it to anyone 
you think might be interested in these parts.

E-mail questions and comments to 70733.3330@compuserve.com

The following parts are currently in stock and available from 
Maryvale Engineering Company:

___________________________________________________________________________


MC145447  Calling Line Identification Receiver with Ring Detector
          (Caller ID chip)

	With this chip and a few other components it is very easy
	to build a CID to 1200 baud computer serial port converter.
	The other required parts are mostly passive: a crystal, the
	phone line interface, and the RS232 level shifters. A
	schematic for the CID > RS232 board is in the data sheet.

	PRICE:	1     = $7.14 ea
		2-5   = $6.78 ea
		6-10  = $6.24 ea
		11-up = $5.35 ea

	DATA SHEET    =	$ .50 ea
___________________________________________________________________________

MC145436P  Dual Tone Multi Frequency Receiver (aka DTMF or TouchTone)

	With the addition of a crystal, this IC receives DTMF signals
	and converts them to binary HEX data. Useful in Ham radio,
	scanner radio, telephone and remote control projects.

	PRICE:	1     = $3.54 ea
		2-5   = $3.36 ea
		6-10  = $3.09 ea
		11-up = $2.65 ea

	DATA SHEET    = $ .50 ea
___________________________________________________________________________

MC14495P1  7-segment LED Decoder/Driver with HEX Characters

	This part will accept a four bit binary input and display
	the number on a single digit 7-segment LED display. It also 
	displays the HEX digits ( from A to F ) in a readable form unlike
	other 7-seg display drivers. The part also includes a latch
	for the data. It's ideal for use with the above DTMF chip.
	( LED display not included ) NOTE: When using this chip with
	the DTMF decoder, a touchtone "0" is displayed an a hex "A".

	PRICE:	1     = $3.46 ea
		2-5   = $3.28 ea
		6-10  = $3.02 ea
		11-up = $2.59 ea

	DATA SHEET    = $ .50 ea
___________________________________________________________________________

HackerPack #6 : Caller ID Package

	This package contains two MC145447 CID Receiver chips and two
	crystal-resistor-capacitor sets required to make the chips
	work. Also included is the complete datasheet for the ICs.
	(Only one of the chips is required to build a working circuit)

	PRICE: $15.00

___________________________________________________________________________

HackerPack #7 : DTMF Decoder Package

	This package contains two MC145436 DTMF decoder chips and two
	crystal-resistor sets required to make the chips function. Also
	included is the complete data sheet along with some application
	circuits. (LED display and driver not included)
	(Only one of the chips is required to build a working circuit)

	PRICE: $9.00

___________________________________________________________________________

HackerPack #8 : Single Digit DTMF decoder/display Kit

	This kit includes all of the components required to build a
	single digit DTMF decoder/display. Audio can be fed from the
	telephone line, scanner radio, HAM radio receiver or any source
	of DTMF (TouchTone) signals. As the tones are received, they are
	displayed on a seven-segment LED display. All 16 DTMF tones can
	be displayed. This kit includes all parts and instructions. No
	printed circuit board is provided but assembly is simple on a
	small perf board available from Radio Shack. A touchtone "0" is
	displayed as a hex "A" on the display. Touchtone 1 throug 9 are
	displayed correctly.

	PRICE: $8.50

___________________________________________________________________________


Odds'N'Ends (no quantity discounts apply)

        Part 					Price	Application
	---------------------------------	------	-------------------
	3.579545 MHz Crystal			$ 1.35  (CID and DTMF chips)
	7-segment common cath LED Display	$ 1.70  (HackerPack #8)
	1 Megohm resistor			$ 0.15  (DTMF chip)
	10 Megohm resistor			$ 0.15  (CID chip)
	30 pF capacitor				$ 0.15  (CID chip)

___________________________________________________________________________


	BACKGROUND:

	Maryvale Engineering is a for-profit company involved in publishing,
	contract engineering, and mail-order electronic sales. This offer
	is not a "net bulk buy", but our regular business. Founded in
	1985, we publish two small newspapers and two directorys concerning
	electrical and electronic news in Arizona and the southwest.

	In the course of publishing the two newspapers, hundreds of new
	product releases cross our desks each year and many are for new
	ICs and electronic components with high hobbiest appeal.

	The focus of our newly formed mail-order enterprise is going to
	be getting hard-to-find new components into the hands of electronic
	hobbiests in small, reasonably priced quantities. (Where else
	can you buy one Caller ID chip?)

	We want to target new, interesting, and hard to get semiconductor
	devices but occasionally a great deal on surplus may allow us
	to offer some odd specials (ask about HackerPack #5, 'Cactus Guts').

	Around the middle of the year, we plan on beginning the publication
	of a quarterly newsletter/catalog which will detail technical
	specs on new components, circuits using the parts, and various
	applications. Eventually we will charge a nominal subscription
	fee ( $4.00/year or less ) but for the time being it will be
	free. (This will be a printed on paper, US Mailed publication)
	To get on the mailing list, send your request to the PO Box
	given below, or E-mail it to 70733.3330@compuserve.com

	We will also E-mail announcements of new ICs when they are
	available along with technical details and application
	ideas. This will be mailed ONLY if you request it. 

TERMS:

	NO MINIMUM ORDER

	We must have payment in advance before processing your order. Personal
	checks are accepted but I give the bank a week to figure out if they're
	good or not. The best bet will always be a money order.

	If sales tax is required for your location, we pay it.

****	I can send copies of the data sheets to anyone who wants them. This
	offer is ONLY being made to folks on the Internet and won't last long.
	Send one first class stamp for each data sheet requested and a SASE to
	the PO box given below. PLEASE ! ! include which data sheet you want!
	Please bear in mind, I DO have to pay for the data sheets.

	For shipping and handling charges, include the amount from the 
	following table based on the destination:

	United States		$ 3.00
	Canada			$ 3.00
	Australia		$ 7.00

	All ICs are packed in ESD safe plastic rails. All loose parts are
	packed in ESD safe plastic bags. The remainder if the packaging
	material is recycled, and/or environmentally freindly. All
	orders are shipped First Class U.S. Mail. We will ship UPS if you
	include the appropriate shipping charge FOB Phoenix, Arizona.

	We strongly recommend combining your order with friends to help
	spread the shipping charges around.

	Send orders, SASE/Datasheet and catalog requests to:

		Maryvale Engineering Company
		PO Box 23786