Apple II Telecom Manual I: Hardware and Transfers

Csa2 FAQs-on-Ground file: Csa2T1TCOM.txt  rev012

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 001- How do I transfer files between my Apple and a PC or Mac?
 002- How do I transfer/convert my A2 word processor files to a PC?
 003- How do I transfer Apple II disks between Apple2 and PC?
 004- How do I transfer files between computers using NULL modem?
 005- How do I NULL-modem Text files without getting garbage?
 006- How do I make a "NULL Modem" cable?
 007- What is the maximum length for a NULL modem connection?
 008- I have a Super Serial Card. What cable should I use? 
 009- How do I make a GS hardware handshake High-Speed modem cable?
 010- What is the fastest modem I can use on an Apple IIe? 
 011- Does what applies to the IIe also apply to the //c and IIgs?
 012- What telecom programs run on Apple II computers?
 013- What are the settings for the Apple Super Serial Card?
 014- What are the Serial Pro card's dip switch settings? 
 015- What are the settings for an Apple Serial Interface Card?
 016- What cable can I use to do NULL modem transfers with my IIc?
 017- What cable(s) can I use to connect a modem to my IIc?
 018- How can I connect a modem with a Dsub-9 socket to my IIgs?
 019- What is the maximum modemming speed I can get from my IIgs?
 020- How can I transfer files from PC to GS using Zip disks?
 021- How do I get an Applesoft program into a PC-DOS computer?
 022- I want to use a faxmodem with my //GS. Is this possible?
 023- Can I do modem-to-modem transfers between my home computers? 

From: Rubywand

001- How do I transfer files between my Apple and a PC or Mac?

     The best, most flak-free way to move stuff between Apple II and PC
or Mac is via a NULL modem connection. This is a direct
machine-to-machine transfer between serial ports with a NULL modem
connector joining modem cables from each computer.

     Other ways of doing a direct PC-Apple II transfer include ADT and
Ap2222. These software packages include A2 and PC programs which let the
user do transfers via serial ports (ADT) or game port and printer port
(Ap2222).  They are, mainly, intended for moving whole A2 5.25" disks.

     Another option is to use a BBS-- perhaps your own company BBS-- or
a website, etc.. You upload from one machine and download with the

     A completly different approach is to move files on diskette. For PC
transfers, this requires that either the Apple II or the PC have a
plug-in card and/or special diskette drive which lets it read diskettes
from the other machine. The mechanics of each machine's diskette
interface are too different to permit Apple II to read a PC diskette on
an A2 drive or PC to read an A2 diskette on a PC drive.

     Depending upon model, installed OS, and available utilities, Macs
can exchange files with Apple II computers via ProDOS and HFS 3.5"
diskettes. Macs with the A2 plug-in board can handle standard 5.25" A2



     If your other computer is a Mac, you can format a Mac HFS
(standard) DS/DD 3.5" disk and the GS can read and write it if you have
the HFS FST installed. That's how I exchange files with a Mac...


From: Rubywand

002- How can I transfer and convert word processor files from an
     Apple IIe to a PC Microsoft format (DOS, Word)?

     There is a Sequential Systems package named "CrossWorks" which 
lets you transfer Appleworks, Word Perfect, text, and other ProDOS files
to a PC and transform them to a variety of PC formats including those
which fit a variety of PC word processors. It includes Apple & PC
software plus an 8' cable which connects your IIe, IIc, IIc+, or IIGS to
a PC. Sequential is at . Their number for
orders is 800-759-4549.


From:  Bill Mackin

003- Is there a way to transfer Apple II disks between a an Apple II
     and a PC?

     Sure. Yesterday I downloaded  It was written by some
guy in Hong Kong.  You buy a 25-pin male parallel port connector and two
8-pin DIP sockets from Radio Shack.  He gives the wiring diagram for
connecting 9 wires between them.  You type in a 6502 assembly program on
your apple at address 300. Save the program, shut things off, hook up
the wire from your PC printer port to the Apple Game Controller socket,
turn them on, and run his programs.

     It copies whole Apple disk images over to the PC, or PC to Apple,
or individual files back and forth!  It works great!  I've already made
26 disk images from my old Apple disks (great for backup, too!) and have
been  playing the games from them, moving games around, etc.

     I only had one problem with the ap2222pc program; the first time I
ran it, my PC was already in Windows and I had printed something to a HP
LaserJet IV from it; when I turned the Apple on after hooking up the
cable, the Apple locked up, giving me several different hi-res graphics
screens in series, no beep, and no cursor.  The problem went away when I
turned the Apple on first, then the PC.


From: Rubywand

004- How do I transfer files between computers using NULL modem?

     You will need a NULL modem connector and each computer needs a
modem cable and telecom program.  A IIe or II+ will also need a serial

  ____________                                        ____________ 
 |  PC or Mac |                                      |  Apple II  |
 |  running a |                                      |  running a |
 |  telecom   | <--modem--> [NULL modem] <--modem--> |  telecom   |
 |  program   |    cable    [connector ]    cable    |  program   |
 |____________|                                      |____________|

    "NULL modem" means "no modem". A NULL modem connector is just a pair
of connectors wired 'back to back' with a few lines switched so that
each computer views the other pretty much as though it were a modem.
NULL modem connectors can be found at Radio Shack for a few dollars or
you can make your own. 

     On the Apple II side, you can choose from several good telecom
programs. Since you would like to be able to do z-modem transfers, good
choices include Intrec's ProTerm-A2 3.1 (Enhanced IIe -- IIgs), MGR
Software's Modem MGR (II+ -- IIgs), AnsiTerm (IIgs), and Spectrum
(IIgs).  You can also choose from many freeware and shareware programs.
Generally, these support x-modem but do not support z-modem. 

     If you're running under a current version of Windows, HyperTerm
works very nicely on the PC side. (For sending Text files from PC to
Apple under HT, be sure to uncheck "send line enders" in the ASCII
settings.)  If there is a choice of terminal emulations, it seems best
to stick with something simple, such as "TTY". A good NULL modemming
program for running under DOS is Telemate, commonly available as
shareware. Many other telecom programs are available and work fine under
current Windows, old Windows, and DOS. Similarly, there is a good
selection of Mac telecom wares.  

     To do transfers, you just connect the modem cable from each machine
to the NULL modem connector. If your PC or Mac has a spare COM port, the
connection can remain in place without disrupting normal net connections
through the other COM port. For a GS, the modem  cable should be a "high
speed" type which allows hardware handshaking and this option should be
set in the GS telecom software. The same is true for other Apple II's
running at 9600 baud or above.

     Set the same format (8-N-1) and baud rate on each telecom program.
(The format will, almost always, already be set to 8 bits-No parity-1
Stop bit.)  A good first-try speed setting is 9600 baud. If errors
indicate this is too fast for either machine, you can move down to 2400
baud. An accelerated GS running Spectrum can connect with modern PC's
running HyperTerm at 56k baud or better.

Note: Spectrum (and most other newer Apple II telecom programs) do not
require that you modify Control Panel settings for speed and
handshaking. Since Spectrum directly accesses the GS serial port, speed,
etc. settings are done in the program. (By the way, this frees-up Slot 2
-- the GS modem firmware Slot-- for any peripheral card which needs to
have its Slot set to "Your Card" in the Control Panel.)

     Place each program in terminal mode-- often, this is the default
mode. Or, the particular telecom program may have menu items or buttons
you select for specific kinds of transfers.

     Next, you will usually select the function (send or receive) on
each machine and the protocol. The protocol should be the same on both
machines. Z-modem is the best choice for most single or multiple file
transfers. Text files can be an exception (see the next question). A
plain ASCII transfer will circumvent most problems but is slower; and,
you may need to send and receive/capture files one-by-one instead of in

     Finally, you will select the file or files to send or "Open".

     Usually, it is best to start Receive on the target machine before
starting Send on the source machine. If you find that one telecom
program or the other does not give you enough time to start Send-- i.e.
it keeps "timing out"-- change the program's "Time Out",  "Inactivity
Delay", etc. setting.

Note: Some telecom programs may expect an end-of-send signal which the
sending program does not supply.  Pressing CTRL-X or RETURN on the Apple
II or ESC on the PC often seems to work okay for terminating the Send.

From: Jeff Blakeney

     You don't need to manually tell Spectrum or other modern telecom
programs to receive a file each time you do a Z-modem transfer. Just
make sure that you have Auto Receives turned ON. In Spectrum the setting
is in the Settings/File Transfer/Receive Options... dialog.


From: Rubywand

005- How do I NULL-modem Text files without getting garbage?

     The main problem in A2-PC Text file transfers is that Text files
created by the PC use a CR _and_ an LF to end a line whereas Apple
II-created Text files use just a CR. So; PC files show up on Apple II
displays with annoying "#" or inverse "?" symbols; and, Apple II files
show up on PC displays with long, un-terminated lines interspersed with
block symbols.

     For PC-to-A2 Text file transfers, Z-modem, X-modem, etc. usually
work fine if you  have some way to deal with the extra Control
characters, mainly line feeds. On the GS, Appleworks 5 does a good job
of automatically cleaning out such garbage; and, Text editors like
ShadowWrite and CoolWriter have options to quickly strip out offending
line-feed Control characters. Some telecom programs, including Spectrum,
have Text editors which can strip out Control characters and perform
other manipulations to clean up a file.

     An alternative is to do a plain ASCII Text transfer. (The PC
telecom program should be told _not_ to add line feeds or "line
enders".)   Depending upon your A2 telecom program, the result may be
saved from your Capture Buffer, captured directly to an on-disk Text
file, or selected and saved from the Scrollback buffer.

     Similarly, for A2-to-PC Text transfers, you can use Z-modem or some
other block transfer protocol if you have a PC utility which can convert
Apple II text to text PC's like. For example, one way to send several
Text files is to put them in a .SHK file, z-modem them to the PC, and
use Nulib (v3.24) to unshrink the files in PC Text format.

     Otherwise, you are probably better off doing a Text transfer. Set
your A2 telecom program to "send LF's". If there is a "Prompting" option
it should be OFF. Do an "ASCII Text", "Plain Text", etc. Send. The PC
telecom program should be set to Receive Text if this option is
available. If it is not, you will be able to select and save the text
from the PC program's display or save the text from some capture buffer.

Note: Some programs with a "Receive Text" option may expect some
end-of-send signal which the sending program does not supply.  Pressing
CTRL-X on the Apple II or ESC on the PC often seems to work okay for
terminating the Send. For example, Telemate will ask if you wish to
abort the transfer-- you answer "Y"es-- but, the file will still be
saved on the PC.


From: Edhel Iaur, Esq.

     Appleworks 5.x seems to do a pretty good job of cleaning up text
files from the net. (e.g. it automatically clears out the annoying LF's
which show up in most text file viewers.)  There is, also, a standard
Awks macro which will get rid of end-of-every-line CR's.


From: Rubywand

006- Does anyone have directions for making a "NULL Modem" cable?

     A NULL modem is two 25-pin female sockets (call them "A" and "B")
wired back-to-back as follows ...

 Socket-A  Socket-B

    1      -> 1
    2      -> 3
    3      -> 2
    4 & 5  -> 8
    6 & 22 -> 20
    7      -> 7
    8      -> 4 & 5
   20      -> 6 & 22

     If you can find a couple old-style Dsub25 plug casings, the sockets
can be mounted and the casings can be glue-gunned together to make a
nice compact unit.

     For GS-PC (or Mac, etc.) transfers, you plug the modem cable from
the GS into one side of the NULL modem and the modem cable from the PC
into the other side. If the PC has a 9-pin serial port connector, use a
9-to-25 adaptor cable to connect to the NULL modem. Similarly, if the
Mac cable has a special connector, use a converter to a male Dsub-25M
connector for plugging into the NULL modem.


007- What is the maximum length for a computer-to-computer
     NULL modem hardware-handshaking connection?

     Most texts agree that around 50 feet is the 'safe' maximum length.


008- I'm using the Super Serial Card. What cable should I use
     to get Hardware Handshaking?

     According to a diagram in the "Modem Works" manual, there is a
special modem cable recommended for connecting to a Super Serial Card to
get hardware handshaking flow control:

SSC side     Modem side
25-pin       25-pin

   2 -------> 2
   3 <------- 3
   4 -------> 4
   5 & 8 <--- 5
   6 <------- 8
   7 <------> 7
   20 ------> 20

For NULL modem transfers, the Modem side plugs into the NULL modem


From: Tae Song (White Wolf)

009- Does anyone out there in Net.Land have the pin connections
     to use for a GS CTS/RTS hardware handshake compatible
    "High-Speed" modem cable?

View is looking into the cable connector/plug at the pins.

Male Mini-Din 8             RS-232 Male Dsub-25M

   6  7  8           01 02 03 04 05 06 07 08 09 10 11 12 13
   3 4   5            14 15 16 17 18 19 20 21 22 23 24 25
    1  2

DIN-8    Dsub-25M   Signal Discription

  3        2        TD  (Transmit Data)
  5        3        RD  (Receive Data)
  4,8      7        GND (Ground)
  2        5        CTS (Clear to Send)
  1        4,20     RTS & DTR (Ready to Send and Data Term Ready)
  7        8        DCD (Data Carrier Dectect)


From: Richard Der

010- I have an Apple IIe and was wondering what is the fastest
     modem I can use on it?

     The Super Serial Card and compatible serial cards max out at 19200.
As a result, 14.4 modems are the fastest modems that can be used on the
IIe. A 28.8 modem will work; but it will automatically switch into 14.4


011- Does what applies to the IIe also apply to the //c and IIgs?

     For the //c, mainly it does. The //c requires a different cable. If
your //c is a IIc Plus, you can use a Macintosh modem cable with it.
These are available in most computer stores.

     What is said about the IIe applies to the IIGS except:

     1) The IIGS port can easily go up to 57600, so faster modems
        are no problem.
     2) The IIGS uses Macintosh modem cables available in any
        computer store.

     3) The IIGS can use its own modem software, such as Spectrum
        which is more powerful and graphical.

     4) You will be able to use your normal PC style internet
        connection when a GS graphical web browser is ready.
        A GS TCP/IP already exists.


From: Gareth Jones

012- What telecom programs run on Apple II computers?

KERMIT: This runs on any Apple II. It comes in DOS 3.3 and ProDOS
versions. It is free. It supports Kermit and XModem file transfer
protocols; VT52, VT100, and dumb terminal emulations. It is a little
harder to set up and use than some other programs, but works perfectly
well once you've done that. On a GS, remember to turn the "DCD Detect"
option in the modem control panel OFF, or it won't work.

Z.Link: a ProDOS system program that requires a IIe, //c, or IIgs. It
supports XModem and YModem file transfers; VT100 and  partial VT220
emulations. The "macro" program that comes with it is simple, but fine
for some things, like auto-entering your password. A nice feature is
that ALL the options are shown and set in a single screen display,
reached by pressing Open-Apple-?. I used this program quite happily for
a number of years, so it is probably worth a download to see if it meets
your needs.

Talk is Cheap 4.0: An excellent program for the IIe, //c, or IIgs. It
requires an accelerator chip (e.g. a Zip Chip) in a IIe or //c to
communicate over 4800 baud. With the accelerator chip, you're fine up to
19,200 baud. It has an excellent scripting language, which was used as
the basis for Spectrum's scripting language. File transfer protocols are
Xmodem (various types, such as 4K xmodem and 1K xmodem) and Ymodem (for
downloads). The manual is a good tutorial for telecommunications. You
may be able to find an early shareware version on the nets or in your
User Group's Library.

ProTerm 3.1: I can't talk too much about this since I haven't used it. A
demo is available for trying out. What I CAN say is that this has been
the most popular commercial telecommunications program available for the
Apple II. The program supports many emulations, every file transfer
protocol I know (including Kermit), and if you have a mouse, it'll give
a mouse and pull-down-menus environment. If you don't have one, you
won't need it.

Telcom: This is a recent discovery for me: a telecommunications program
for the IIgs with Xmodem uploads and downloads, ymodem downloads, VT100
or ProTerm Special Extended terminal emulations. It runs only on the GS,
and uses a mouse-and-menus interface implemented on the text screen. It
is free, because it is a never-finished commercial product. The author,
Jawaid Bazyar, would like your comments on it. This is similar to Z.Link
in features (except no macros), and cheaper, but GS only.

Spectrum: This is the ONLY GS/OS telecommunications desktop program
(i.e., standard menus, the system clipboard for cutting and pasting,
etc.). VERY strong scripting language that even supports sounds, icons,
fonts, colours, clickable buttons (like HyperCard). It supports most
terminal emulations, many file transfer protocols (e.g. Zmodem, though
not Kermit. Yet). The author and publisher have released version 2.0 and
are committed to developing it further.

ANSITerm: from Parkhurst Micro Products. Paul Parkhurst's program is
supposedly the best colour ANSI graphics available on a GS. It supports
macros, many file transfer protocols, and there is a demo version to try
out. GS users only.


From: Rubywand

     Another very good program is Modem MGR from MGR Software. It runs
on any Apple II and works with a wide range of modems, 80-column boards,
and clock cards. MM supports popular protocols from x-modem through
z-modem and many terminal emulations. The last number I have for MGR
Software is 714-993-0294.


From: Tom Kelly

013- What are the settings for the Apple Super Serial Card?

Recomended slots:
    slot 1 for terminal use (e.g. printer)
    slot 2 for communication use (e.g. modem)
Jumper Block:
    for communication use label is upside down (arrow points up)
    for terminal use label is right side up (arrow points down)

Note that RS-232-C signals on the SSC use negative-true logic; that is,
they are true at 0v and false at +5 volts.
SW1 Dip Switch Settings:

    Baud      SW1-1     SW1-2     SW1-3     SW1-4     SW1-8
    50        on        on        on        off       not used
    75        on        on        off       on        "
    110       on        on        off       off       "
    135       on        off       on        on        "
    150       on        off       on        off       "
    300       on        off       off       on        "
    600       on        off       off       off       "
    1200      off       on        on        on        "
    1800      off       on        on        off       "
    2400      off       on        off       on        "
    3600      off       on        off       off       "
    4800      off       off       on        on        "
    7200      off       off       on        off       "
    9600      off       off       off       on        "
    19200     off       off       off       off       "
Switch Settings For Communication mode:

    SW1-5; SW1-6; SW1-7 are all set on
Data          Parity    Stop      SW2-1     SW2-2     SW2-3   SW2-4
Bits                    Bits
7             none      1         on        off       off     on
7             odd       1         on        off       on      off
7             even      1         on        off       off     off
7             none      2         off       off       off     on
7             odd       2         off       off       on      off
7             even      2         off       off       off     off
8             none      1         on        on        off     on
8             odd       1         on        on        on      off
8             even      1         on        on        off     off
8             none      2         off       on        off     on
8             odd       2         off       on        on      off
8             even      2         off       on        off     off
Note: SW2-1 thru SW2-4 settings can be overridden by software.

    ON  for linefeed out
    OFF for no linefeed out

    ON for baud rates greater than 1199 baud

    OFF in communication mode

    Not used
 Connector Pin Assignments

 10-Pin    Dsub-25
 Header    Connector          Signal Name
    1         1               Frame Ground
    2         2               Transmit Data (TXD)
    3         3               Receive Data (RXD)
    4         4               Request To Send (RTS)
    5         5               Clear To Send (CTS)
    6         6               Data Set Ready (DSR)
    7        19               Secondary Clear To Send (SCTS)
    8         7               Signal Ground
    9        20               Data Terminal Ready (DTR)
   10         8               Data Carrier Detect (DCD)

Pins 1-7 and 2-7 are set together to determine the SSC pin to be read
for the Hardware Handshaking signal. Generally set to monitor Pin #20.
Common Configurations: [Don't Forget The JUMPER Block]
       Hi Speed Modem                  ImageWriter I/II
      1234567  1234567                 1234567  1234567
ON     XXXXXX  XXXXXX                     X XX  X  XX
OFF   X              X                 XXX X     XX  XX


From: Kevin M. Carr

014- Could someone who has an Applied Engineering Serial Pro
     card please post a list of the dip switch settings for
     the 2 banks of switches?

     I use an AE Serial Pro in my  //e to connect to my ImageWriter II. 
All of the DIP switches are set to OPEN (switch down).  The switch block
next to the printer interface connector is for hardware handshaking
signals. (Copied without any permission whatsoever from the AE Serial
Pro User's Manual.)

 o Switch 1, when closed, select pin 4 (Request to send) as the flow
control handshaking line.  Some printers which use this line are: Data
General TP2; Heath H-25; Olympia ESW102/103; QUME Sprint 5; and
Smith-Corona TP1

 o Switch 2, when closed, selects pin 11 which is, according to RS-232-C
specifications, undefined and is used by some serial printers as a
printer-ready signal. Some Centronics, Texas Instruments, and Epson
serial printers may use this pin.

 o Switch 3, when closed, selects pin 19 (Secondary Request to Send) as
the handshaking line.  Some of the printers that use this pin are the
Anadex DP8000/9000, Bell TP-1000, Lear Seigler 310, NEC 3500/7700, and
Digital Equipment (DEC) LA-series serial printers.

 o Switch 4, when closed, selects pin 20 (Data Terminal Ready) as not
only the device-available handshaking line but also as the data-flow-
control line.  Some Diablo, C.Itoh, Okidata, QUME, Tectronics, or Xerox
printers may use this handshaking signal.

 o When all of the switches are open, Data Terminal Ready (Dsub-25 pin
20) is the only line monitored as the hardware handshaking line from
your printer. This supports most popular serial printers.

     The second set of DIP swithces (close to the front of the card) is
for generating Maskable (IRQ) and Non Maskable (NMI) interrupts from the
6551 Asynchronous Communications Interface Adaptor (ACIA) chip and the
6818 clock chip.  The swithces select the type and source of interrupt
request.  Normally all switches are in the OPEN position.

      o Switch 1: IRQ from 6551

      o Switch 2: NMI from 6551

      o Switch 3: IRQ from 6818

      o Switch 4: NMI from 6818


From: Cyrus Roton <>

015- What are the switch settings for the old
     Apple Serial Interface card?

The switch settings are as follows:

1    2    3      baud rate
on   on   on     110
off  on   on     134.5
on   off  on     300
off  off  on    1200
on   on   off   2400
off  on   off   4800
on   off  off   9600
off  off  off  19200

sw 4  off = enable delay after CR

5    6    line wt   video
on   on    40       enable
off  on    72       disable
on   off   80       disable
off  off   132      disable

sw 7  off = enable LF after CR


From: Supertimer

016- I've heard that I can use some sort of printer cable to do
     NULL modem transfers with between my IIc and a PC. Which cable?

     Get an "Apple IIc to ImageWriter I" cable. It has a DIN-5 plug on
one end and a standard Dsub-25 plug on the other with the correct line
swapping for NULL modem. Depending upon whether your PC connection is to
a 25-pin or 9-pin port and whether or not an extension cable is used,
you may also need a Dsub-25 to Dsub-9 cable and/or a Dsub-25 gender
changer. (The latter are standard items at many computer stuff stores.)

From: David Empson

017- What kind of cable should I use to connect a modem
     to my IIc?

Here is the pinout of the IIc serial port looking at the back of the

  DIN-5F (female)
   socket with
Apple's numbering

   5       1
    4     2

The functions are:

1  Handshake Out (nominally DTR)
2  Data Out (TxD)
3  Ground
4  Data In (RxD)
5  Handshake In (nominally DSR)

To connect a IIc to a typical modem use the following pinout
for a non-hardware handshaking cable:

IIc                Modem
DIN-5M             Dsub-25M      DIN-5            Dsub-25M
                                 plug          male connector 
1 Handshake Out    20 DTR
2 Data Out          2 TxD      1       5   ,--------/ /---------.
3 Ground            7 Gnd       2     4    \  1   2 ... 12  13  /
4 Data In           3 RxD          3        \  14   ...   25   /
5 Handshake In      6 DSR*                   `------/ /-------'

*You might want to use pin 8, DCD in some cases.

To connect a IIc to a modem with a 9-pin connector you can use
the pinout below for a non-hardware handshaking cable:

IIc                 Modem
DIN-5M              Dsub-9M      DIN-5            Dsub-9M
                                 plug          male connector 
1 Handshake Out     4 DTR 
2 Data Out          3 TxD      1       5   ,--------/ /---------.
3 Ground            5 Gnd       2     4    \  1   2 ...  4   5  /
4 Data In           2 RxD          3        \   6   ...    9   /
5 Handshake In      6 DSR*                   `------/ /-------'

*You might want to use pin 1, DCD in some cases.

The IIc cannot do hardware handshaking** very well, but this is as close
as you can get:

IIc                 Modem
DIN-5M              Dsub-25M      DIN-5            Dsub-25M
                                  plug          male connector
1 Handshake Out     4 RTS
2 Data Out          2 TxD       1       5   ,--------/ /---------.
3 Ground            7 Gnd        2     4    \  1   2 ... 12  13  /
4 Data In           3 RxD           3        \  14   ...   25   /
5 Handshake In      5 CTS                     `------/ /-------'

** Note that you need comm software which supports hardware handshaking
on the IIc to do this properly. I expect ProTerm does, but Z-Link and
Talk Is Cheap almost certainly don't.

The IIc's handshaking lines have annoying side effects, which cause
problems with hardware handshaking:

1. The "Handshake Out" signal is implemented to mean "I want to send
data" (the official and original meaning of RTS).  If you turn off the
output handshake line, the IIc will stop sending data.  For a hardware
handshaking modem, RTS is supposed to mean "You are allowed to send me
data" (from the computer's point of view).

   If the computer tells the modem to stop transmitting, the computer
will also be unable to transmit.  This will reduce the rate at which
data can be transferred bidirectionally, but doesn't cause any other

2. The "Handshake In" signal is implemented to mean "There is receive
data present" (the official meaning of DCD).  If the incoming handshake
line is disabled, the IIc will stop receiving data (ignore any data on
RxD). For a hardware handshaking modem, CTS is supposed to mean "You are
allowed to send me data" (from the modem's point of view).

   If the modem tells the computer to stop transmitting, the computer
will also be unable to receive, and will discard any data sent by the
modem   while CTS is not active.  This can cause screen corruption and
loss of data blocks or acknowledgements during a file transfer, which
will require retransmission. It is only likely to be a problem while a
lot of data is being sent, so is more likely to cause problems during a
file upload than a download. If the comms software is quick enough, it
can drop RTS immediately when CTS is lowered, which will prevent the
modem from sending any more data.

The original IIc motherboard has another problem: it uses a cheap method
of generating the clock frequency for the serial ports.  Most
implementations based on the 6551 chip use a 1.8432 MHz crystal, which
gives exact baud rates, but the IIc takes the master system clock
(14.31818 MHz in an American IIc) and divides it by eight to produce
1.7898 MHz.  The 3% decrease in clock frequency produces a 3% drop in
the baud rate, which is enough to prevent operation with some serial
devices, particularly intelligent modems running at 1200 bps or faster.

This is not always a problem, and I have successfully used one of these
IIc's with a ZyXEL U-1496E modem and a direct connection to a IIgs at
9600 bps.  I have had problems in other cases.

You cannot identify whether you have this motherboard except by opening
up the computer and looking for a tell-tale component.  (I don't have
the details handy.)

You can make a reasonable guess at whether you have the original
motherboard by checking which firmware version is installed in the IIc. 
Get into BASIC, and type PRINT PEEK(64447).

If the value displayed is 255, then you have the original ROM, and
almost certainly have the original motherboard, though it might have
been modified to use a crystal.

If the value displayed is 0, then you might have the original
motherboard or the revised one.  (This ROM version supports the UniDisk
3.5 drive.)

If the value displayed is 3 or 4, then you have the "memory expansion"
version of the firmware, and almost certainly have the latest
motherboard, which includes a memory expansion slot under the keyboard.

In theory, the IIc's maximum baud rate is 19200.  Whether it can
actually keep up with that rate is another question.  9600 should be


From: SuperTimer

018- I have a good modem that has a standard RS232 serial port
     and responds to standard "AT" commands; but, it has a Dsub-9
     connector. Is there an adaptor or cable that will let me
     connect the modem to my IIgs?

     Yes; the cable to use is a Macintosh to Hayes Modem cable. This can
be found in any computer store. Just ask for a Mac to modem cable. All
new Mac cables are usually hardware handshake cables, so you should have
no trouble with higher speeds.


019- What is the maximum modemming speed I can get from my IIgs?

     The IIGS can use much faster modems than is indicated by the
Control Panel. Using a hardware handshake cable and with the right third
party driver (like the one in Spectrum), the serial port can go up to
57600 baud.


020- How can I transfer files from PC to GS using Zip disks?

     The trick is not to use MS-DOS, but instead use HFS. On the PC, you
need to install a program called MacDrive 98. This program allows
Windows 95 to read, write, and format HFS volumes. On the IIe, you need
a freeware program called A2fx.  A2fx will read any HFS volume, even

     With HFS as a link, you will be able to move files from your PC
onto Mac/HFS formatted Zip disks (no need to make 32MB partition) to
your IIe via A2fx. The reverse transfer needs another program, but I am
pretty sure that one exists to let the PC read ProDOS volumes.


From: Dave Althoff

021- How do I get an Applesoft program into a PC-DOS computer
     in text format? Both computers have modems, but I have no
     terminal program for the Apple.

Make sure that your serial ports are connected together, and run the
comm program on your PC. Now, for our purposes, lets assume you have the
serial card in Slot #2.

Force the PC into terminal mode.

Make sure the ][ is displaying a *40-column* screen.

Now, try typing "IN#2" on the ][.  Type something on the PC.  It should
appear on the Apple.  (Cool, ain't it?!)

In fact, try typing "PR#2".  On either computer.  Now, you should get an
Applesoft prompt on your terminal screen!  In fact, you can use the PC
comm program as a keyboard for your ][!

All right, at this point, you should have data flying back and forth
between the two machines.  On the ][, type "POKE 33,33".

Now, on the PC, tell your comm program to start a text capture.  Tell it
to add line feeds after carriage returns.

On the ][, load the BASIC program, and type LIST.  The program listing
will appear on the Apple screen and be dumped into the PC comm program's
capture buffer.

To break communications, type "IN#0" and "PR#0" on the ][.


From: Jeff Blakeney

The only things I might add is that you have to make sure that the PC
and II's baud rates are the same.  Preferably 19200 if you want a speedy

Second thing is that once you have typed IN#2 and PR#2 (or 1 if the
serial port is in slot 1) is that everything should be typed using the
PC keyboard.  This is because anything you type on the II after those
two commands will NOT appear on the II's screen.  It is much easier to
type it on the PC as everything you type and would normally be displayed
on the II will be displayed by the PC's terminal program.

I have actually used this method to transfer BASIC programs from my PC
to my II with 8 data bits, 1 stop bit, no parity at 19200 bps. It sure
makes things easier.


From: Dave Althoff

Actually, if you are working in 40-columns at least, when you do IN#2,
the console input is redirected through the SSC.  Fortunately, the SSC
is kind enough to include keyboard reads in its data input loop, so IN#2
does not disable your keyboard.  Likewise, so long as you are looking at
the 40-column screen, PR#2 redirects the output hook to the SSC, but the
SSC does writes back to the screen.  So you don't lose your monitor


From: Brian Hammack

022- I want to use a faxmodem with my //GS. Is this possible? I
     tried all kinds of choices from the install menu of Proterm
     3.1. Is there a certain string required?

     Yes. Only difference between a fax modem and a "regular" one is the
fax instruction set. I have a 28.8 fax modem on my GS.

     Most likely, you have to use a "CTS/RTS" parms setting in the
Install, and an init string that handles things correctly. The book for
my 28.8 ultrageneric suggested AT&F [use default settings] but that
doesn't do the job. So the string I am using to trip all the triggers


Before that, I was using something that worked except at 2400:



From: John M. Davies

    Just pointing out, the INIT string is not a function of the comm
program, it is a command to the modem itself, so any good comms package
should be able to send any sort of init string to the modem.

    ATZ is the standard Hayes command to 'RESET MODEM TO DEFAULT'
settings, and must be on it's own line, hence the <return> character is
required. After that, most modems will also respond to standard Hayes
command set commands, but the individual modem in use will usually have
an extra set of commands provided by that modems manufacturer, to
support the unique 'features' of that particular brand of modem.

    You will need to obtain the command set booklet provided with the
modem, to read the list of extra commands. Sadly, like printers, each
manufacturer has their own idea of what a good command set is, so no two
modems extended command sets are identical.

    If you don't have the booklet, try searching the web site of the


From: SuperTimer, Greg Buchner, David Empson 

023- Can I do modem-to-modem transfers between my home computers?

     Maybe. One way is to use your in-home phone line. To connect, you
take a phone off the hook and connect using telecom programs on each
computer. You can connect and do transfers once the lines are free of
beeps, tones, etc. which indicate a phone is off the hook. If your phone
company is one that keeps beeping you forever, the connection will not
work. An alternative which some suggest is using a phone extension cord
to connect the modems.