NOTE: MDM730 SUPPORTS AUTO-DIALING AND AUTOMATIC CONTINUOUS REDIALING
FOR THE FOLLOWING MODEMS:
SIGNALMAN ANCHOR MARK XII
HAYES SMARTMODEM 300 OR 1200 MODEMS
U. S. ROBOTICS 300/1200 MODEM
PMMI 103 S-100 PLUG-IN MODEM
IT CAN STILL BE EASILY USED WITH OTHER EXTERNAL MODEMS
ITH MANUAL DIALING SUCH AS THE BELL 212A, RACAL-VADIC,
ETC. IT SUPPORTS UP TO TWO LONG-DISTANCE DIALING SYSTEMS
(SUCH AS 'MCI', 'SPRINT', 'TYMNET', ETC. FOR TOUCH-TONE
DIALING SYSTEMS.
INTRODUCTION:
------------
MDM730 enables a computer to communicate with another computer.
This is normally done by using standard telephone lines but with special
audio tones sending serial data. Two common speeds are used, depending
on the facilities available -- 300 Baud or 1200 Baud. A "modem" is used
which provides these audio tones. This is an acronym for "modulator and
demodulator". The one section (modulator) provides the audio tones for
sending over the telephone line and the other section (demodulator) then
converts those audio tones back to digital pulses the computer uses to
receive the incoming data.
The modem itself is a hardware utility, usually costing around $75
to $200 for a typical 300 Baud device and from $250 to $800 for a system
offering 1200 Baud as well as 300 Baud. Some of these (such as the PMMI
S-100 modem board) plug directly into the computer itself, while others
are totally independent of the computer and use an interconnect cable
(usually a RS-232 type) to control the external modem. A Bell 212A is
an excellent example of this type modem. Other examples would include
the Racal-Vadic, Hayes Smartmodem, U. S. Robotics, Signalman Anchor, etc.
The program discussed in this guide allows each computer involved
to directly control its own modem, converting DC pulses into audio tones
which are sent to (or received from) the telephone line. (The standard
1200 baud transmissions use "DPSK" (dibit phase shift keying) instead of
"AFSK" (audio frequency shift keying).
For short distances, no modems are required as the computer can
provide the necessary digital voltages. This discussion is centered
around systems intended for use over distances ranging from several
miles to literally around the world.
FEATURES:
--------
A program to communicate with another computer can range from very
simple to very complex. MDM730 is one of the more complex such programs
available today. It started in 1977 as a relatively simple program. It
was called MODEM at that time. It was intended to be used primarily as
a means of exchanging programs with other people in other cities. Since
that time a number of other (very useful) features have been added, in
addition to improved methods of program transfer. A list of some of the
features offered by this particular program include:
1) Ability to talk with another computer via keyboard at each end.
(Called the "terminal mode".)
2) Ability to operate a remote mainframe computer such as TYM-SHAR,
or special data bank systems now commonplace. This includes
"bulletin board" systems for receiving, sending or just read-
ing messges or other types of information.
3) Ability to upload (send) or download (receive) programs from other
computers whether TYM-SHAR, data banks, remote hobby systems
or just another individual in another location.
4) Ability to copy incoming information on a printer. If the print-
er is too slow to copy the data directly, the extra characters
back into a large storage buffer until they can be printed.
5) Ability to copy incoming data into memory for automatic transfer
to a disk file.
6) Accomodates any computer clock speed up to 25.5 MHz. in 0.1 Mhz.
increments for uniform results. (The clock speed is actually
of modest interest, it is only used for setting timing loops.)
7) Advanced type of error detection (CRC or Cyclic Redundancy Check)
using automatically generated high-speed lookup tables.
8) Ability to send any of 11 different pre-programmed function keys.
(These keys are very easy to reset, using a special external
program.)
9) Automatic disconnect from the telephone line when using CTL-N, or
"X" as an option during file transfer. Two other disconnect
commands with the PMMI modem.
10) Additional features of special interest to those using the PMMI
103 S-100 plug-in modem, the U. S. Robotics 300/1200, the
Anchor Signalman Mark XII, the Hayes Smartmodem 300 or 1200
or other "Hayes-compatible" modems. Those features basically
include automatic dialing and redialing (if requested) until
the other computer finally answers.
a) Automatic selection of a particular phone number from
a library of names and numbers. (These phone numbers
can be very easily changed by using a special external
program.)
b) Automatic dialing for alternate long-distance systems
(where auto-dialing touch-tone modems are used).
c) Entry of a hand-typed number. Although it might be as
simple to manually dial the number as hand-type it, it
can then be automatically redialed indefinitely.
USING THE PROGRAM THE FIRST TIME:
--------------------------------
For now, we shall assume the program is ready to use on your equip-
ment. (Normally the user must make some modest changes to the program
before it can be used. This includes changing the port numbers and some
other personal options. These will be covered later in the section that
describes how to adapt it to your equipment.)
When the program is brought up is shows this display (if using the
PMMI modem):
MDM730 - (type M for Menu)
Version for PMMI S-100 modem starting at port: C0H
B>>COMMAND: x
The cursor stops at point "x:" waiting for some sort of command.
Typing a "M" followed immediately by a RETURN, shows the first page of
a 4-page help guide. If you do not have a PMMI modem, you would have
seen this (or a customized heading for your particular equipment):
MDM730 - (type M for Menu)
Version for Non-Pmmi modem
B>> COMMAND:
In this case only a 3-page help guide is used, since the 4th page
is used to assist those with the PMMI modem. It tells them a little
about changing from originate to answer mode, how to change Baud rates,
how to disconnect, etc.
Several commands are similar to those already used for CP/M, such
as 'ERA', 'DIR' and the ability to change disk drives and user areas.
This adds tremendous flexibility while remaining in the modem command
mode. To change disk drives, just say:
B>>COMMAND: A: <RET>
and you are in the same user area on the A: drive. You can also
say:
A>>COMMAND: A: 12 <RET>
to change user areas. When finished (using this example), say:
A12>>COMMAND: CPM <RET>
and you will go back to CP/M with the original driver and user area.
OPTIONS:
-------
There are 6 primary options and 13 secondary options that may be
typed on the command line. In additon there are over 35 commands ranging
from single character to three characters that can be used (such as DIR,
ERA, LOG, etc.) Those are listed on the menu. (The exact number varies
depending on whether you have the PMMI modem, etc.)
Primary Options: E, L, M, R, S, T
E = Echo mode (special type of full duplex)
L = Local modem (no remote echo, half duplex)
M = Menu display showing features that are available
R = Receive a file from remote facility
S = Send a file to a remote facility
T = Terminal mode (full duplex, echo provived remotely)
Secondary Options: A, B, D, J, O, Q, R, S, V, X, 0, 1
A = Answer mode (used only by PMMI modems)
B = Batch mode -- allows automatic multiple file transfer
(This is normally only used from modem-to-modem as
no RCP/M system supports batch mode file transfers.)
D = Disconnect when done, stay in MDM730
J = Command mode when finished with a file transfer
O = Originate mode (used only by PMMI modems)
Q = Quiet mode, special purpose feature rarely used except if
operating through a "BYE" program.
R = Receive data shown on CRT during file transfer
S = Send data shown on CRT during file transfer
V = Visual inspection of an ASCII file being transferred. Not
often used as most ASCII files are now "squeezed" for
minimum transfer time and disk space.
X = Exit to CP/M when finished, disconnect from phone line
0 = Odd parity (PMMI modem)
1 = Even parity (PMMI modem)
Although you can get the following information from the help guide
in MDM730 itself, showing it here will allow us to discuss the various
features in somewhat better detail.
(*) INDICATES PMMI, ANCHOR, HAYES AND US ROBOTICS ALL APPLY.
- - - - - - - - - - - - - - - - - -
THE HELP GUIDE, PAGE 1:
----------------------
Single Letter Commands
? - Display current settings
^ - Function key intercept character, then (0-9)
M - Display the menu
E - Terminal mode with echo
L - Terminal mode with local echo
T - Terminal mode
For copying text to disk use T (or E or L) FILENAME.TYP
Start or Stop toggles described on subsequent screen.
R - Receive CP/M file using Christensen Protocol
S - Send CP/M file using Christensen Protocol
COMMAND: R (or S) FILENAME.TYP
R and S can use the following subcommands:
B - Bulk transfer using wildcards (e.g., *.*)
D - Disconnect when done, return to command mode
Q - Quiet mode (no messages to console)
V - View <R> or <S> bytes on console
X - When done, disconnect, go to CP/M
The single letter commands may also be used on the
command line when the program is initially executed.
Hit any KEY to CONTINUE
- - - - - - - - - - - - - - - - - -
DISCUSSION OF HELP GUIDE PAGE 1:
-------------------------------
There are basically three types of commands that may be used with
this program:
1) Single-letter commands shown on page one.
2) Three-letter commands shown on page 2, and
3) Control-<char.> commands shown on page 3.
Going down the list:
? - shows current parameters. As these are closely tied in with some
of the other options, we shall show a typical example later
in this discussion.
^ - shows the function key intercept character. This may be easily
changed using an external program. (You may prefer 'escape'
or some seldom used control-character.)
NOTE: typing this character while in the command mode will
display all the programmable function key definitions
with the exception of the log-on string which uses
CTL-L.
M - shows the menu a page at a time. You may abort after any page is
shown with a control-C.
E - terminal mode with echo. When talking with another terminal also
also using MDM730 (or a comparable program), one of you must
send an "echo-back" so you can both see what the other person
is typing. This is needed for full-duplex operation. Usually
the person originating the call will type "E" instead of "T".
However either may do this. If "both" use the echo mode, the
program usually starts typing a string of feedback characters
since both computers are re-sending the same character over
and over. You can stop this by just returning to command mode
(type control-E) and then retyping "T" rather than "E".
L - terminal mode with local echo. Shows what you are typing but does
not send an echo of the other person's typing back to him.
Can be used at both ends, in place of one person using "E".
Both "E" and "L" are useful at times for some types of modems
that do not use full-duplex, or for some main frame units that
run half-duplex. The combination of "T", "E" and "L" gives an
excellent choice to use on various systems. Normally the "T"
mode is sufficient except when talking with another person and
then the "E" mode at one end or "L" mode at both ends will
provide normal results. If the remote system does not supply
a LF after a CR, you can get that from the 'TLF' command.
T - puts the program directly into "terminal mode", allowing it to
send from the keyboard to the other computer, and to copy any-
thing coming from the other computer with the exception of
file transfers (use "R" to receive those).
R - used only for receiving files from the other computer. These are
usually sent in binary form with either checksum verification
or more commonly, CRC (Cyclic Redundancy Checking). If ready
to receive another file, you have several choices, depending
on the program used by the other computer. After notifying
him you are ready (or will be very shortly), you can type:
B>>COMMAND: R HELLO.DOC <RET>
and when he starts to send, you will receive the program which
then goes directly to the disk. You could also have said:
B>>COMMAND: RB <RET>
This is called the "Batch mode" and is an extremely useful way
to receive programs automatically, from another computer using
a similar program. He will use the batch mode for sending the
programs and that automatically provides the file names at the
receiving end. In this manner, large numbers of programs can
be transferred completely automatically, including full disks.
(Assuming you care to pay the toll calls for the time it will
take!)
NOTE: The ideal way to receive batch mode would be:
B>>COMMAND: RB <RET>
since you may not know in advance how many programs he
will be sending.
NOTE: While receiving a file, any errors will be shown
on the console CRT, indicating that portion of the
program is being repeated. If the file finishes
transferring normally, it will have been received
error-free. Those error notices are merely to let
the user know a momentary problem caused a resend.
The error messages indicate phone line quality.
S - used only to end programs. Similar to "R" but sends instead of
receives. If the other system is ready to receive, you could
then type:
B>>COMMAND: S HELLO.DOC <RET>
It will tell you how many records are involved and how many
minutes and seconds it will take to send the program. If the
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computer. If too many consecutive errors occur (normally set
at 10), the transfer is terminated. The 'batch mode' may also
be used for sending:
B>>COMMAND: SB HELLO.* (sending batch mode)
will send all files starting with HELLO, or can send just one
file, or can send several non-related files in this manner:
B>>COMMAND: SB HELLO.DOC XDIR.COM TERM.*
etc. Be sure to put a space between the various files. You
can include the 'X' option:
B>>COMMAND: SBX HELLO.* MDM730.LBR MDM730.AQM
When the file transfer is completed it disconnects from the
phone line and reverts to CP/M. This allows you to be absent
when the file is finished, offering an advantage when sending
lengthy files.
- - - - - - - - - - - - - - - - - -
THE HELP GUIDE, PAGE 2:
----------------------
Three Letter Commands
CPM - Exit from this program to CP/M
DIR - List directory and space free (may specify drive)
