All about the Ma Bell
circuit - termination, wiring, and terminal hardware most commonly used in
the Bell system
Doing An End Run
Around The Local Telephone Company - by using Point To Point Wireless
Service
Modem connection - Tips
on how to connect the modem in all circumstances, very useful tips for business
travellers
Pacific Telephony
Design Tutorials and Articles - a good collection of tutorials
Antique Telephone
Collector's News
Bell
System Home Page - schematics, drawings, tables, photos, and other
information pertaining to telephones produced by Western Electric for the Bell
System prior to 1984
Cyber Telephone Museum - An
Exhibit of Common & Rare Antique Telephones
Historic Telephony
- telephony history and old telephones
Telephony history pages from
Mike Sandman - old telephone related ads and articles
The Strowger Telecomms Page -
information about old electromechanical telephone exchanges
Tribute to the
Telephone - history, schematics, trivia, photos, links and other telephony
related pages
Disassembly
Of A Touch-tone Phone - what is inside modern telephone
How
telephone recording adapters work
Lifting
Ma Bell's Cloak Of Secrecy - A New Look At Basic Telephone Systems, zipped
file containing Phrack Magazine issue
24
Loop current technical bulletin
- what are the problems when the loop current is too low or high
Phone line audio
characteristics - article from Radio Guide Magazine
Phone Line Basics - basics of
lines and their characteristics
Phone System
Tutorial I - read also part
II
Telephone Line
Indicator design - information on the characteristics of telephone lines
Telephone
line audio interface circuits - telephone hybrid circuits described and more
Telephone
Signals and Circuit Conditions - as used in the USA and Canadian Telephone
System
Tips for Correcting Bad Phone
Lines
Understanding telephones -
technical introduction to how telephones work, also archived at http://massis.lcs.mit.edu/telecom-archives/archives/technical/how.phones.work
Adding
a Jack to an Existing Phone Line - step by step instructions for wiring used
in USA
Adding
a Second Line to Your Existing Phone Jacks - for wiring used in USA
An
Introduction to Providing Your Own Telephone Wiring
Phone
Man's Advice for Wiring Your Home Phone Lines
JACKS and PLUGS
- Universal Service Order Codes to identify tariffed services and equipment
Telecom
Tools - some of the most used telecom installer tools are also found in the
average home tool kit
Telephone
installation accessories manufacturers - connectors, cabling systems, tools
and more
The Basics of
Telephone Wiring
What
do all the wire colors mean?
comp.dcom.fax FAQ
comp.dcom.fax
FAQs
Rockwell class 1 and
2 fax command information - fax modem commands
Solwise Guide to Computer
Communications - includes fax standard table
Computer can be used to perform lots of fuctions in modern telephony systems.
This link collectains mostly information on linking computers and traditional
telephone systems. There is a separate link
section for Internet telephony.
General information
Telephony
Overview and Applications
The PBX Goes
PC - voice-enabled modems and new software standards provide inroads to
computer telephone integration
Wide Area
Network Telephony - tutorial explains how to use internet telephony software
coupled with peripherals to build a complete internet or intranet based
telephone system
Resource pages
Ken's CT-Page - starting point
for Computer Telephony surfing
Pulver.com - information on computer
telephony
Telecom Tutorials and
Articles - In-depth Information on Telecommunications, Computer Telephony,
Internet Telephony and More
Necessary techniques
Audio/Telephony
Integration with AC '97
Echo Cancellation
for VoIP - echo cancellation is necessary technology in long distance
telephony, especially in computer based telephony
Voice over Frame Relay
Voice over IP
- large linkk section
Voice Over the
Internet - Today it's a toy. Tomorrow it may be a crucial part of corporate
telephony, article from Data Communications
magazine September 1996
Modems and computer telephony
How Do
I Stop my Phones From Interrupting My Modem - telephone mini-FAQ
How to connect your
computer modem to a hotel phone
Programming
Java Telephony API
Writing
Computer Telephony Software for Digital Telephone Networks
Numbering of
Telecommunications Networks
Telehallintokeskus - Telecommunications
Administration Centre
Televerkkojen
numerointiperiaatteet - telephone numbering in Finland, text in Finnish
Televiestintää
koskevia lakiotteita teletoimintalaista ja rikoslaista - erityisesti säännösten
rikkomisen seuraamuuksista kertovia kohtia
THK:n antamat määräykset
- some telecom regulations in Finland
Usein kysyttyjä kysymyksiä
teleliikenteestä ja -tekniikasta
FCCC Part 86
- connection of terminal equipment to the tlepehone network
The
Telecommunications Terminal
Equipment Directive - 91/263/EEC
Technical characteristics of tones for the telephone service are listed in ITU-T
Recommendation
Q.35 (1988). Infortunately that document is not freely available (can be
ordered from ITU-T if you are willing to pay),
so the information available in the following documents might be useful if you
are looking for free information on telephone line signaling.
Basic signaling
ITU-T
E-Series Recommendations Excerpts - telephone information tones
Telephone
ringing circuits - how to detect ringing and how to make phones ring
Telephone
Signals and Circuit Conditions - as used in the USA and Canadian Telephone
System
What is Ringer Equivalence?
DTMF dialling
DTMF - Most Of What You Wanted To
Know
DTMF
coding and decoding using ADSP-2100 - pdf file with good text and some
source code
DTMF
Encoding and Decoding In C
Generating
DTMF tones using computer soundcard
Touch-Tone
Information - information on touch tone standards
Touch Tone
WAV file generator - MS-DOS text-mode program for generating WAV files with
DTMF sounds
WAV files of
DTMF 0-9, dialtone and busysignal - zipped file from Gene's
Telecommunications Links and Phone Home Pages
Called ID
CallerID: The Next Advance in
Telephone Services - introduction to called ID service concept
Caller
ID circuits and information - information and circuits for different systems
used USA and Finland
Caller ID Links - lots of
links to web Sites related to caller ID
Caller Identification - What
Standards are Involved?
Computer Caller ID
FAQ
FCC Caller ID page - general info
nad FAQ
Frequently
Asked Questions About Caller-ID
Frequently Asked Questions About
Caller-ID - from TELECOM Digest
FX602
Calling Line Identifier IC - for deconding called ID systems used in USA and
UK, datasheet has example circuits
Guidelines for
implementation caller ID service in Finland (GFI9702) - information about
DTMF based caller ID system in use in Finland
Specs for UK caller ID
- FSK system used in UK, info in zipped text file from Darrens
Odds & Sods page
UK Caller ID FAQ homepage
- information on setting caller ID system on PC
Audio signal coding
Companding
systems used in telephone PCM systems - A-law and my-law
Misc
E-Series
Recommendations Excerpts
How message waiting lights
work - description of different message waiting light systems
FCC Interference
Handbook - electronic version of FCC Interference to Home Electronic
Entertainment Equipment Handbook
QST October 1992 Lab Notes
on Telephone EMI - amateur radio telephone interference
Radio Interference to
Telephones - articled how to avoid it
Radio
signal suppression for telephone sets - Bell Systems Practices SECTION
500-150-100
RF Elimination Technical
Bulletin
What to do if you
hear radio communications on your telephone
Telephone
Schematics for Western Electric Phones - Schematics, Drawings and Tables
from Station Service Manual to view/download
Building
and using phone patches - article from Ham Radio Magazine October 1985
Hands-Free
Telephone - circuit to interface telephone handset connector to stereo
heaphone and small microphone
How do I hook
the Sound Blaster output to play over the phone line - zipped file
Playing a Mac through a
standard telephone line - how to get sound from computer to telephone line
Phone
"Hold" With Music
Simple Phone Tap
- will record any conversation on any phone on same line, the circuit seems to
be a bad design because it does not provide proper isolation and has too low DC
impedance (can keep you line off-hook all the time)
Simple
telephone test circuit - get telephone audio to mixer or send audio to
telephone
Telephone
Audio Interface - uses transformer and capacitor to isolate the line from
external equipment, diode based surge protection on output
Telephone
line audio interface circuits - telephone recording, telephone line to mixer
and telephone hybrid circuits
Telephone Record
Control - allows you to connect any tape recorder that has a mic and remote
input to a phone line and automatically record both sides of a conversation when
ever the phone is in use
Telephone Recorder
- lets you record your phone conversations automatically
Telephone
Tap - wire your telephone conversion to amplifier or tape recorder
Phone Busy Indicator
- simple busy indicator, does not meet regulations of many countries
Phone-In-Use
indicator - simple design idea for indicator
Phone in
use circuits - two designs
Phone In Use
Indicator
Ringing Phone Light
Flasher - when the phone rings light flashes, good ring detector example
circuit
Telephone In-Use
Indicator - A blinking LED lets others know when you are on-line!
Telephone
In-Use Indicator - versions for LED indicator and relay output
Telephone Line
Indicator design - information on the characteristics of telephone lines and
circuit which connects to a telephone line and indicates whether or not the line
is in use (seems to be quite good design)
Telephone
privacy adapter - revents other telephones from hearing your call and
disturbing your modem connection
Telephone recording switch -
starts you tape recorder using a relay when you pick up telephone
Caller
ID circuits and information - information and circuits for different systems
used USA and Finland
Caller
ID / DTMF Audio Decoder Sources & Links
Caller
ID / DTMF audio decoder
Démodulate
DTMF SSI 202 - DTMF demodulator circuit using SIS202, text in French
DTMF
Generator/Decoder - tutorial with example circuit diagrams
DTMF Microphone -
connects to PC game port
DTMF Products for you - DTMF
decoder can be powered from a 9V battery or from your parallel printer,
schematic and windows demo program, design by Schmidt Technologies
DTMF Tone Decoder
with LCD Display - based on Basic Stamp microcontroller
UK Caller ID to PC
serial port - decodes 1200 bps FSK signaling used in UK, zipped file, specs
of UK caller ID coding are available at http://www.nitebeat.demon.co.uk/bt_clip.zip
Dialler circuits
Un composeur automatique de numéro
téléphonique - PC controlled DTMF dialler
Test equipments
Bi-Directional
Telephone Line Simulator - with Dialtone and Ring signals
Cut Phone Line
Detector - can be used to alarm security system
Digital/Standard
Phone Line Tester - make sure that the line is suitable for modem use and
your PCMCIA does not damage if you plug it in
Digital/Standard
Phone Line Tester - telephone line polarity and current detector
Misc telephone accessories
Building
a telephone answering system - laboratory report
Puhelimen vaihtorele
- telephone relay system which disconnects other telephone from line when one
telephone is in use, description in Finnish
Ringing Phone Light
Flasher - when the phone rings, lights connected to circuit flash
Ringing Phone Light
Flasher
Telephone
Controlled Night Light - when the telephone rings, or when the handset is
lifted, the night light is turned on and remains on while the conversation takes
place
Telephone "distinctive
ring" switcher - zipper demo file from Dunfield
Devellopment System
Telephone Hold
Button
Phone
rang indicator light - will detect the ring signal, energize the relay which
latches up, and the LED comes on and stays on till you push a switch
Telephone Recorder
- lets you record your phone conversations automatically, notice that this
circuit does not provide isolation between telephone line and the recorder
Telephone
recording circuits - how they work and some example circuis
Intercom circuits
Bi-Directional
Telephone Line Simulator - works as complete intercom for two telephone,
provides Dialtone and Ring signals
Cheap theatrical intercom
system - intercom system made of old telephone
Connect two
standard office telefax machines via 2 meter ham radio (at 2400 bps) -
zipped file
Fax
to Faxmodem interface circuit - can be also used as telephone intercom
circuit or connecting two modems together
Use
old telephones as intercom
Surge protection
Telephone
line surge protection - information and circuits
Telephone
line surge protector circuit - also archived at ftp://nic.funet.fi/pub/doc/telecom/technical/lightning.surge.protect
Telephone transmitters
Telephone bugging is an illegal practice. The following circuits are for
educational use. They are illagal in many countries.
FM Telephone Bug
FM
Telephone Transmitter
Phone-bug
- A simple transmitter that is powered from the phoneline, zipped file
Wireless
Phone Jack - report what's inside it
Misc telephone circuits
Phone
Gadgets - conference call and hold button
Telephone-related
ASCII Schematics - wide collection of telephone circuits
Signaling
DSP Solutions for
Data/Facsimile Modems - application note from Texas
Instruments, includes info on many usefula algoriths
MT8870 Datasheet
- popular DTMF decoder IC from Mitel,
datasheet in pdf format
Line interfacing
3750 V of
Isolation Not Required at the Network Termination - technical note in pdf
format from Midcom
dBm to RMS
voltage chart - Microsoft Excel 4.0 format from Midcom
Technical Notes
Gyrator
circuit - simulate large coils electronically
Handy Line Interface Design Hints!
How to
measure Total Harmonic Distortion (THD) of a transformer or other passive device
- none page Word file from Midcom
Technical Notes
Impedance
measurements of telephone lines - two page technical note shows the
impedances measured on the telephone line, for more information read the whole
article in Microsoft Word format
Low cost,
CTR 21 compliand DAA for Europe - application note from Midcom
Midcom
Technical Note Technical Note Index - tech notes about telephone
transformers
Optimum hybrid design
- application note in pdf format
Optocouplers
Isolate Modem Data Access Arrangement - Appnote from Siemens
Semiconductors in pdf format
Overview of
IEC 950 - EN 60950 (BABT), UL 1950 / CSA 950 - A Brief Overview of what it
is and what is important when dealing with transformers in pdf format from Midcom
Technical Notes
Return Loss
Calculations - four page note explains how return loss can be determined and
contains a MathCad analysis, an Excel spreadsheet analysis and a QuickBASIC
program listing, zipped file from Midcom
Technical Note library
Transformer
Equivalent Circuit
Transformer
Modeling Tips - technical note in pdf format from Midcom
Transformer
Seminar Notes - companion to the seminar entitled "The
Telecommunications Transformer: low-cost solution to product reliability and
continuing regulatory compliance" by Dave LeVasseur, in Word 6.0 format,
from Midcom, new
version progressing, also available in zipped
format
Two and Four Wire
Transmission - how hybrid transformer is alligned
Wiring
inside telephones
Automatic terminal equipment
Phone Remote
System - a telephone interface that allows the householder to give
instructions to appliances from outside, application note from SGS-Thomson
Telephone
& Answering System
The Official Small Switch Technology
Site - information about telephone switch kit published in Circuit
Cellar Ink magazine
Telephone ringing
Telephone
ringing circuits - how to detect ringing and how to make phones ring
Telephone Ring
Generator
Telephone
Ring Generator - will ring a telephone once every 10 seconds
Telephone ICs
Voice
Switched Speakerphone ICs (TEA1095) - pdf file
The following telephone hacking circuits are here only for educational purposes.
Most of them don't work anymore and connecting them to telephone network is
illegal.
2600 Magazine - link to famous pheaker
magazine web pages
A
Zillion Different Ways To Make Your Very Own Red Box
FoNe BoXeZ - beige, black and
other pheaker's boxes
G-Files - hacking, boxing and
geek humour
Pheaking
Sites Links - links from Yahoo
Phrack - information
about everything you shouldn't know about telephone
Some
Box Plans - plans for many telephone hacking boxes
The Hacker's
Handbook - very early version of the book that was later banned in Great
Britain in 1985
The Official
Phreaker's Manual
RoDI
ISOC
IWA
ARTT
RTS
WQC 2003 
ISAQ 2005
