CP/M MODEM PROGRAM DOCUMENTATION
by Mark M. Zeiger and James K. Mills
11/04/80
This program uses the file transfer routines written by Ward
Christensen in his CP/M file transfer program (V2.0 as of 8/6/79)
and is compatable with his program in single file transfer mode.
Multi-file transfers are only possible between two systems running
the program described below.
This program has three functions:
1. Communication
2. Program transfer
3. Modem control (for PMMI Modem)
COMMUNICATIONS
The program may emulate a terminal or echo data back to sender (act
as a computer).
Terminal Mode - 'T' Option
The terminal mode may be called with or without a file name.
If a file is specified (it should be a new file), then
anything received by the modem may be saved in memory and
later written on disk. The save feature is toggled ON/OFF by
Control-Y. On an IMSAI the front panel LEDs will indicated
that memory save is toggled on by showing the binary value of
the ASCII character received. For those with no front panel, a
colon (:) will be printed at the beginning of each line when
memory save is active. The colon will not be transmitted over
the modem nor will it be saved in memory.
If a file is not specified, then memory save can not be
activated.
If the memory buffer is full (the buffer is from the top of
the program to the bottom of BDOS), the contents are
automatically written to disk (but the file is not yet
closed). Communications may then continue with the buffer
reinitialized. The computer with which you are communicating
must accept the X-ON and X-OFF (Control-Q and Control-S)
conventions or data will be lost.
When communications are over, use Control-E to exit from the
Terminal mode and enter the Menu. The file to which you are
writing must then be closed by using the 'WRT' command. If
this is not done, all data will be lost. I decided not to
close the file automatically since there will be times when
you leave terminal mode and then decide to re-enter. This may
be done while in the Menu by using the 'RET' command. You may
re-enter Terminal mode and save in the same file as many times
as you wish as long as you have not closed the file with the
'WRT' command.
While in Terminal mode, Control-T will put you in File
Transfer mode. This will allow you to send the contents of an
ASCII file over the modem. This routine does no error checking
and there are no protocols specified between this program and
the receiving computer other than that it should be ready to
receive data via the modem. Control-X will cancel the
transfer.
Computer mode - 'E' Option
This mode echos data received by other computer. Only one
computer may be in this mode at one time. There is no save
feature in this mode. Useful if you wish to communicate with
somebody running the terminal portion of the program.
File transfer - 'S' and 'R' Options
These features are the same as in the CP/M Modem program
written by Ward Christensen except that upon completion of the
transfer, control returns to the Menu unless the secondary 'T'
option has been selected. In the latter case, control returns
to Terminal mode. Remember that if you are operating a remote
computer using a timesharing program (such as Ward
Christensen's "BYE"), the remote should be instructed to send
or receive in the quiet (Q) mode as a secondary option.
Examples of commands for sending and receiving are listed
below.
Multi-file transfers
Using the B (batch) secondary option, more than one file and
ambiguous filenames may be transferred. To send files, use the
primary option "S" and the secondary option "B" (along with
any other secondary options and baudrate). To receive the
files being sent, use the "R" primary option and the "B"
secondary option. Files may not be named since filenames are
sent by the sending program, but a disk drive may be specified
(or else the files are written to the default drive).
Backup option
There is a byte at the beginning of the program (106H) that
will create a backup file if a file on the disk has the same
name as the file being received in multi-file transfer (see
MODEM.SET). If this byte is set to 0FFH, a backup file will be
created. If it is zero the file on the disk will be deleted
before the new file is received. If you are running CP/M 2 and
a file on the disk is designated R/O or SYS, a backup will be
created whether the byte at 106H is set or not.
Be careful - if you are running CP/M 1 and the drive on which
you are receiving has an R/O file with the same name created
by CP/M 2, the R/O file can not be accessed (found, changed,
erased, etc.) by CP/M 1. You will therefore have two files
with the same name when you are running CP/M 2. To fix this
problem, use CP/M 1 to change the name of the file that is not
R/O. Then use CP/M 2 to do what you want with the R/O file.
Examples:
The sender enters SBOT.600 B:*.COM to send all the COM
files on disk B. Also specified were originate mode 600 baud
(PMMI modem) and return to terminal mode when done.
The receiver enters RBA.600 to receive all the files
being sent on the default drive (also answer mode at 600 baud
for PMMI).
The sender enters the command SB.600 ASM.COM *.HEX B:M*.*
which will send ASM.COM from the default drive, all the HEX
files from the default drive, and all the files starting with
"M" from the B drive. [note that neither 'A' or 'O' were
specified: default is to whatever mode the PMMI is in
currently]
Multifile transfers may only be done from the menu. It may not
be specified when the MODEM program is called. In other words
A>MODEM SAB *.COM will result in an INVALID OPTION error
message.
Return to Menu - 'M' option
When asked to select an option, 'M' returns to Menu.
The MENU
If the Modem program is entered with no option, the Menu is
called. The Menu gives the choice of selecting the standard
options as defined by Ward Christensen (T, E, R, and S). The
Terminal mode has been greatly expanded as described above.
The "R" and "S" commands must be called with a filename or you
will be required to enter the primary command (S or R) and the
filename again (but NOT the secondary options). If you want
multi-file transfers, then the "R" option does not need a
filename.
RET - You may also enter terminal mode using the 'RET' command, but
no data will be saved since a file may not be named with
'RET'. Use the 'RET' command to RE-ENTER Terminal mode after
it has first been entered with the 'T' option. If this is
done, you will still be able to save the communications if you
were doing so before you exitted the terminal mode.
WRT - The 'WRT' command must be used after leaving Terminal mode.
This writes the last buffer to disk and closes the file.
Failure to use the 'WRT' command results in loss of all data
and a file of length zero.
DEL - The 'DEL' command erases the most recent file accessed in
Terminal mode. Useful if you decide after communications that
you don't want to save information just gathered.
CPM - The 'CPM' command reboots and returns to CP/M.
XPR - The 'XPR' command is a toggle which causes the menu to be
printed or not printed. Initially the menu is on unless the
program is called with the "X" option (ie. A>MODEM X ).
DIR - The 'DIR' command lists the directory of a CP/M disk. A drive
may be specified (ie. DIR B:) or the default drive will be
listed. After the directory is listed, the menu will not be
printed whether XPR mode is on or off. If XPR mode is on and
you wish to see the menu, hit return.
FOR THE PMMI MODEM
DSC - To disconnect you must use the 'DSC' command in the Menu.
The original secondary options for the PMMI Modem (as defined
by Ward Christensen) are "A" (answer mode), "O" (originate
mode), and baudrate selection. See examples below.
Once answer or originate and a baudrate have been selected
(ie. SO.450 NAME.TYP), any subsequent options will use the
same mode and buadrate. If you want to change the baudrate, it
may be done without changing the mode. For instance, if you
are in originate mode at 450 baud, then the command 'R.600
NAME.TYP' will allow you to receive a file at 600 baud in
ORIGINATE mode. If you want to change the ans/orig mode, then
you MUST select the baudrate again or it will default to 300.
CAL - Allows dialing of number. If a connection to a computer is
established, you will be able to select options (usually
TO.xxx). If no connection is made after 15 seconds, [changed
to 25 seconds in distributed version] then you will
be informed and be given the option of redialing or returning
to the menu. The dial routine may also be specified when the
Modem program is called by entering A>MODEM C. No secondary
options will be accepted when the "C" option is used. [Note:
you cannot type: CAL 312-545-8086 -- well, you can, but the
number will be ignored and you will have to retype it when the
program asks for it -- in the latest version (11/4/80)
there is a 'library' feature such as in DIAL.ASM. To use the
CAL function, type CAL and a return at the menu. You will see
a message 'WAITING FOR DIAL TONE' then a lot of stuff about
entering the number. At this point you may type in a number,
or you may type a letter which will designate one of the
library numbers (which you must insert at assembly time).
^B - Control-B while in Terminal (or Echo) mode allows change of
baudrate "on-the-fly." A carriage return gives 300 baud; all
other rates (110-600) must be explicitely stated.
LISTING OF COMMANDS AND OPTIONS
Primary options
S - send a CP/M file (must specify file/s)
R - receive a CP/M file (must name file unless B sec opt used)
T - terminal mode (specify file if memory save wanted)
E - terminal mode with echo
M - return to menu
X - used only when program is called to initially
toggle menu off
Secondary options
B - multi-file mode for sending and receiving files
T - return to terminal mode after transfer (memory save off)
R - view what is received in file transfer
S - view what is being sent in file transfer
V - view what is being sent or received in file transfer
T - Terminal mode (used with remotely controlled computer)
O - originate mode (PMMI modem)
A - answer mode (PMMI modem)
.xxx - baud rate xxx (xxx = 110-600 PMMI modem)
EXAMPLES (fn = filename, ft = filetype)
Send file, originate mode, 300 baud
SO fn.ft
Send another file, same mode and baudrate
S fn.ft
Receive file on B drive, 600 baud, ans mode, view what is
being received, return to terminal mode
RART.600 B:fn.ft
Send all COM files, no messages on console, same baud and mode
as last transfer
SBQ *.COM
Send two files from two different drives
SB A:fn1.ft1 B:fn2.ft2
Receive files being sent by above on drive A (baudrate must be
same and modes opposite)
RB A:
Terminal mode, save communication in file, 300 baud (default
rate), originate mode (in terminal must type CTRL-Y to start
save, in menu must type "WRT" to close file)
TO fn.ft
ASSEMBLING THE PROGRAM
You must use Digital Researches' MAC to assemble the program.
The files required are MODEM.ASM and MODEM.LIB. MACROS.LIB
does not actually contain any macros in the true sense, but it
does contain routines that are necessary for the program to
run (MFACCESS however does use nested macros as real macros).
If you have a PMMI and an IMSAI, you may assemble the file as
is. If you do not have an IMSAI with a front panel, change
IMSAIBYTE to 'FALSE' (near the beginning of the program). If
you wish another character instead of the colon to indicate
when memory save is active, change "MVI A,':' " to "MVI
A,'char' " in the "TERM" routine where 'char' is the printing
character you would like at the beginning of each line when
memory save is active.
If you do not have a PMMI, change the byte to 'FALSE' and put
your modem status and data ports in the appropriate equates.
The labels 'MODRCVR' and 'MODSNDR' should be the same as
MODRCVB and MODSNDB (the bits tested) if your UART uses
positive logic (JZ) and should be zero if your UART uses
negative logic. If you have a Z-80 (or maybe a fast 8085),
change the 'FASTCLK' byte to 'TRUE'. If any port or modem
initialization must be done, put the initialization routine in
the area labeled INITMOD (replacing the PMMI initialization
routine). See MODEM.SET for more details.
If you have a D.C. Hayes Modem, you may incorporate the
routines from MODEM.ASM V2.0 (as of 8/6/79).
You should also note the comment in the INBUFF routine near
the end of the program.
Any problems or bugs, please call me:
Or latest revisor:
Mark M. Zeiger James K. Mills
198-01B 67th Ave. 824 Jordan Place
Flushing, N.Y. 11365 Rockford, IL 61108
(212) 454-6985 (815) 398-0579