  Viewer Instructions - Press M for a monochrome display or C for a color
  display. Use the Up and Down Arrow keys to scroll up and down. Use the
  Page Up and Page Down keys to move a page at a time. Use the Home and
  End keys to jump to the beginning or end. Use the Esc key to exit.
  -----------------------------------------------------------------------
  
  
  FAX SCANNER AND PRINTER v1.0     Bruce Seiler     12/20/94
  **********************************************************
  
  
  I. Introduction
  ***************
  
     These notes describe an economical way to use your fax machine as
  a full page scanner and printer. All required parts are available at
  Radio Shack and cost less than $10 total.
  
     A scanner will allow you to convert custom drawings, photographs,
  logos, etc. to graphics files that can be read by application programs.
  With optical character recognition (OCR) software, you can transform
  scanned text such as memos and magazine articles into editable word
  processor format. Commercial full page scanners cost more than $500.
  Handheld scanners are less expensive (about $100) but are difficult
  to use since they can't scan sections wider than 4 inches in one pass
  and they must be pulled slowly and evenly across a page to produce a
  distortion-free image. Using your fax machine a scanner solves these
  problems.
  
     Printers are expensive and few people can afford a spare. Yet you
  may already have one. Your fax machine can also function as a two to
  four page per minute back-up printer.
  
     The idea behind using your fax machine as a scanner or printer is
  simple. Imagine that you have two separate phone lines entering your
  house and that your fax machine is plugged into one line and your
  computer fax/modem is plugged into the other. You could then call your
  computer fax/modem from the fax machine and send yourself a document.
  You could also send a document from your computer to your fax machine.
  Of course, this isn't practical because you'd have to pay the phone
  company an installation fee plus monthly charges for a second line.
  To avoid this, we will simulate a phone line connection between a fax
  machine and a computer fax/modem using some simple parts.
  
     No electronics experience is necessary to build the phone line
  simulator. If you can twist a few wires together and plug in a couple
  of connectors, you can build this circuit.
  
     These instructions are being distributed as shareware and describe
  the circuit completely. You won't need additional information to build
  or use it. All I ask for is a small registration fee of $10 if you are
  pleased with the results. Registered users will be notified of updates
  and enhancements. I am available by phone or mail to provide technical
  advice. See the Registration section below.
  
  
  II. Parts List
  **************
  
                                     Radio Shack     Radio Shack
  Part                  Quantity     Part Number     Price   
  ****                  ********     ***********     ***********
  
  9V Battery
  Snap Connector        1            270-325         $1.39 / pkg of 5
                      
  150 Ohm Resistor,       
  1/4 Watt              1            271-1312        $0.49 / pkg of 5
  
  Modular Telephone
  Jack                  1            279-355         $2.19
  
  Modular Duplex
  Jack                  1            279-357         $3.99
  
  Miscellaneous -  tape, 9 Volt transistor radio battery
     
     
     The Modular Telephone Jack is a 2 inch by 2.5 inch plastic shell
  with a female phone connector in it. Four wires exit from the back.
     
     The Modular Duplex Jack is a small plastic part that allows you to
  plug two telephone lines into one phone connector. It's sometimes
  called a Phone Line Splitter or a Y Connector.
     
     You can use just about any kind of tape. Electrical tape, masking
  tape, or cellophane tape are all fine.
     
     The 9 Volt battery is the standard type sold in supermarkets and
  hardware stores everywhere.
     
     The parts listed above cost $8.06 in all. If you shop around, you
  can do better. The phone company often gives away the Modular Telephone
  Jacks for free. The Modular Duplex Jack is available in many hardware
  stores for about half the Radio Shack price.
  
  
  III. Wiring Diagram
  *******************
  
  Figure 1 - Phone Line Simulator Wiring Diagram   
          
          150 Ohm Resistor
    *---------/\/\/\/---------*     * => twist wires together & cover
    |                         |          with tape
    |                         |
    |                         | Modular             Modular
    | red wire                | Telephone Jack      Duplex
    |                     x x | x x x x x x x x x   Jack     Phone Cord to
    | +                   x   |    green        x   o o o o  Fax Machine
  -----                   x   |    wire         x   o     o ============>
   ---   9V Battery &     x   ----------- x x x x o o     o
  -----  Snap Connector   x               x     x         o
   ---                    x   ----------- x x x x o o     o
    | -                   x   |    red    | |   x   o     o ============>
    |                     x   |    wire   | |   x   o o o o  Phone Cord to
    | black wire          x x | x x x x x | | x x            Computer
    |                         |           | |                Fax/modem
    |                         |     black | | yellow
    |                         |     wire  | | wire
    |                         |         not used
    --------------------------*           
  
     
     The diagram above is duplicated in the file FIGURE1.TXT. To print it,
  use the DOS command COPY FIGURE1.TXT PRN.
  
     Another view of the wiring diagram is provided by a self-displaying
  graphics file. To see it on a computer with VGA display hardware, press
  F1 now. To see it on a computer with EGA display hardware, press Ctrl
  and F1 now.
  
     The graphics figures in these notes have also been stored in PCX
  format so that you can examine or print them with your own viewer or
  word processor.
  
  
  IV. Construction
  ****************
  
     Construction is easy. Connections are made by simply twisting wires
  together and covering them with tape. The wires coming from the modular
  telephone jack have fork-like spade connectors at the ends. Just wrap
  the wires around the spade connectors. The black and yellow wires coming
  from the modular telephone jack aren't used. You can cut these off if
  you wish or just push them out of the way.
  
     The parts are small enough that all of them will fit inside of the
  modular telephone jack. Secure them with tape to form a compact and
  rugged unit.
  
     It's a good idea to check your wiring after building the circuit,
  but you don't have to worry about damaging your fax machine or computer
  even if the simulator is wired incorrectly. The voltages used are well
  below the level that can cause harm.
  
     Note that an on-off switch isn't included. The circuit doesn't draw
  power from the battery unless it is connected to the fax machine or
  fax/modem. Even then, only a small leakage current flows until either
  the fax machine handset is lifted off its cradle or the fax/modem goes
  on-line. At that time, about 20 mA flows through the circuit since each
  active phone connection presents a DC load of roughly 400 Ohms. To
  maximize battery life, just disconnect the phone cords when you're
  finished scanning or printing.
  
  
  V. Using the Phone Line Simulator
  *********************************
  
     To use the simulator, first plug the modular duplex jack into the
  modular telephone jack. Then plug a phone cord from the socket labeled
  "Line" on the fax machine into either one of the sockets on the
  simulator's modular duplex jack. Plug a separate phone cord from the
  socket labeled "Line" on the computer fax/modem into the other socket
  on the modular duplex jack.
  
     A connection diagram is shown in Figure 2. Press F2 now to view it
  in VGA mode or Ctrl and F2 to view it in EGA mode.
  
     Next, start up your computer's fax software.
     
     On your first attempt to use your fax machine as a scanner, you'll
  realize that the simulator doesn't provide a way to put a ring signal
  on the phone line. This isn't needed for the following reason:
  
     Fax programs have two receive modes - an auto receive mode where
  the modem becomes active after a few rings and a manual receive mode
  where you click icons or press hot keys to put the modem on-line.
  
     The key to using your fax machine as a scanner is the manual receive
  mode. To initiate a fax transfer, lift the handset on your fax machine
  and press the start button. Then click the icons or press the hot keys
  that force your fax software to manually receive a fax. The sequence
  isn't important. You can also force your fax/modem into manual receive
  mode first and then lift the handset and push the start button on your
  fax machine.
  
     Popular fax programs include Winfax Lite, Winfax Pro, and Dosfax
  by Delrina, Quick Link II for Windows and DOS by Smith Micro Software,
  and Bitfax by Bit Software. The clicks/keys used by each to manually
  receive a fax call are listed below:
  
  
     Winfax Lite     -  Click the Receive button (5th button from left).
  
     Winfax Pro      -  Click Receive, Manual Receive Now.
     
     Dosfax          -  From the Dosfax screen, select Receive, Manual
                        Receive.
     
     Quick Link II   -  From the QLII screen, click Fax, Manual Fax
     for Windows        Receive
                        or
                        from Fax Manager, click the - (minus) sign, Manual
                        Fax Receive.
     
     Quick Link II   -  After loading Receive Fax, press Alt and ; (semi-
     for DOS            colon).
     
     Bitfax          -  After setting Answer Mode in the Configuration
                        Menu to Manual Receive, press Alt and Ctrl. 
     
  
     If you're using software not listed here, check its documentation
  to find the manual receive method. 
  
     The phone line simulator will also allow you to use your fax machine
  as a printer if you first configure your fax software to ignore the
  absence of a dial tone. This is done either by adding the Hayes command
  X3 (don't wait for dial tone) to your setup string or by deselecting
  "Dial Tone Detect" in your fax software setup menu. The following list
  describes how to do this for popular fax programs. Other fax programs
  are configured in similar ways.
  
     
     Winfax Lite     -  By default, Winfax Lite ignores dial tones. To
                        be sure, however, click File, Setup, Fax, More.
                        Then add X3 to the end of the string in the
                        Initialization box, e.g., AT&F...X3\ where ...
                        symbolizes other commands. The \ sign is a pause
                        command that may or may not be present.
  
     Winfax Pro      -  Click Setup, Fax/Modem. Delete the X in the
                        Detect Dial Tone box.
     
     Dosfax          -  Go to the Dosfax directory and type the command
                        SETUP at the DOS prompt. Delete the X in the                      
                        Detect Dial Tone box. Note that you must run
                        the SETUP program from DOS. The setup menu that
                        you get from the Dosfax screen doesn't include
                        all configuration settings.
  
     Quick Link II   -  Click Setup, Modem Setup, Options. Delete the
     for Windows        X in the Detect Dial Tone box.
     
     Quick Link II   -  Select Setup, Modem Setup. Change the Dial String
     for DOS            entry to ATX3DT for tone dialing or ATX3DP for
                        pulse dialing.
     
     Bitfax          -  At the Bitfax screen, press F6 (configure).
                        Change the setup to read Dialing Prefix: ATX3
                        and press F10 to save it.
     
     
     After configuring your software you can print a file by sending it
  as a normal fax transmission over the simulator lines. When your fax
  program prompts you for a telephone number, enter any number such as
  555. When you hear tones from your fax/modem, pick up the fax machine's
  handset and press the start button to begin printing.
  
  
  VI. Notes on Resolution, Gray Scale, and Graphics File Formats
  **************************************************************
  
     Fax machines usually provide these two levels of resolution:
  
     Coarse - 200 dots per inch horizontal by 100 dots per inch vertical
     Fine   - 200 dots per inch horizontal by 200 dots per inch vertical
  
     The selection is made by dip switches or function keys on the fax
  machine. You should use the Fine setting for best results. If you scan
  a document or picture at this setting and then print it, you'll get
  quality close to that of an HP III laser printer (300 by 300 dots per
  inch) and a lot better than the view produced on a computer screen
  (about 80 by 60 dots per inch).
  
     Some newer fax machines provide Superfine resolutions of 300 or
  400 dots per inch.
  
     Many fax machines provide 16 to 64 gray scale levels and can thus
  reproduce photographs with good clarity. Some fax machines provide
  only two levels - completely black or completely white - but are fine
  for scanning text, line art drawings, and some high contrast photos.
  
     Your fax software will probably save scanned (faxed) documents in
  its own graphics file format. Since nearly all application programs
  can read PCX files, most fax programs provide a way to convert their
  graphics files to PCX files. Winfax Lite, for example, saves faxes in
  files with the extension FXR. To convert a Winfax Lite FXR file to a
  PCX file, click View, File, Export and enter a name in the File Prefix
  box. The FXR file will then be converted to a PCX file that you can
  use in other applications. Other fax programs allow you to export
  their files to PCX files in similar ways.
  
     An excellent shareware program for converting between various
  graphics file formats is Graphics Workshop from Alchemy Mindworks Inc.,
  Ontario, Canada. Both DOS and Windows versions are available. You can
  download it from many BBSes or contact Alchemy Mindworks directly at
  1-800-263-1183.
  
  
  VII. Theory of Operation
  ************************
  
     A brief description of telephone line connections will help you to
  understand the operation of the simulator.
  
     A simplified diagram of a telephone at one location connected to a
  fax machine at another location through a telephone company switching
  office (the local loop) is shown in Figure 3. Press F3 to see it now if
  you have a VGA display. Press Ctrl and F3 if you have an EGA display.
     
     A battery powers the line at a 48 Volts DC and provides energy to
  close relays at the switching office and to operate circuits in the
  telephone and fax machine. The battery at the switching office is
  coupled to the phone line through a high inductance coil (actually
  part of a relay that notifies the phone company that a call is in
  progress). The coil allows DC current to flow in the phone lines but
  forces audio frequency AC signals to follow a path around the battery.
  
     Current flow in the local loop also puts most fax machines into
  send or receive mode. If you connect such a fax machine directly to a
  fax/modem without the simulator and try to scan a document, the fax
  machine will run in copy mode rather than send mode. If you try to
  receive a fax without the simulator, the fax machine won't go on-line
  when you press the start button.
  
     To build a phone line simulator, we could reproduce the local loop
  circuit exactly using a 48 Volt battery and a high inductance coil. But
  48 Volt batteries and high inductance coils are expensive and difficult
  to find.
     
     Luckily, for our purposes the battery voltage doesn't have to be that
  high and the inductance provided by the coil isn't really necessary.
     
     The telephone company uses a relatively high battery voltage to
  counteract drops in long lines to customers' homes. Since the simulator
  lines run only 20 feet or so, we can get by with less. The voltage only
  needs to be high enough to get about 20 mA flowing through the circuit.
  
     The coil can be replaced by a 150 Ohm resistor since almost any kind
  of decoupling between DC and audio signals, even if imperfect, will work
  over a short distance. Some of the audio signal will pass through this
  resistor, but the fax machine and fax/modem have enough drive to overcome
  the loss.
  
  
  VIII. Registration
  ******************
  
     Considerable effort went into this shareware project. Please show
  your appreciation and register by sending $10 to:
  
     Bruce Seiler
     14 Thomas St.
     New Providence, NJ 07974
  
     Registered users will be notified of updates and enhancements. I am
  available to answer your technical questions by phone at 1-908-464-7877.
  You can also write to me at the address above.
  
  
  IX. Legal Statement
  *******************
  
  Here's the standard legal disclaimer:
  
     The author assumes no responsibility for damage, loss, or personal
  harm caused by the use of this software or any of the information in
  it.
  
  
  Enjoy!...
  