CP/M/CPM_CDROM.iso/cpm/modems/modem2/modem.doc

Text File | 1994-07-13 | 7KB | 217 lines

DOCUMENTATION ON THE MODEM PROGRAM AS OF 05/09/79
        ----------------

MODEM.ASM is a multi-function communications program
for use with the CP/M operating system.  Its primary
function is the transfer of files between CP/M systems.
The transfer is accomplished via a block mode, with
headers and checksums to ensure data validity.  Automatic
retry, up to 10 times, is attempted for every sector
transmitted.  The user is given an option to quit, or
retry after 10 consecutive errors occur.

Also supported is a terminal mode which allows the computer
to function as a terminal to a time sharing system, CBBS,
etc, and a similar program, but which echos all received
characters, such that two people running MODEM can com-
municate keyboard-to-keyboard, one running in terminal
mode, and one running in echo mode.  This is frequently
done to "test the line" or to see how high a baud rate
can be supported before beginning file transfers.

Planned future enhancements include the ability to place
data received (while in terminal mode) into memory, and
write it out to a disk file.

As "delivered" the program supports a PMMI S-100 modem
at primary address 0C0H, and will run unmodified.

A "PMMI" equate can be changed to false, and appropriate
changes made to the various control, status, and data ports
and bits, allowing the program to be used with virtually
any modem or acoustic coupler.  Anyone modifying the
program for the IDS, HAYES, or other popular modems is
advised to do so such that the original program functions
are preserved, i.e. add in a HAYES EQU 1 and then in the
code, say IF HAYES or IF PMMI, etc.  This will allow
other users to use the program by just changing the
equates.
            ---

The program is named MODEM2.ASM (or COM) on the disk,
to indicate that it is an extension of the MODEM.ASM which
was distributed on the CP/M user's group disk 25.  It is
expected that the user will rename it back to MODEM once
any earlier versions of this program are erased.

COMMAND FORMAT:

    MODEM option
 or    MODEM option.baudrate
 or    MODEM option fn.ft
 or    MODEM option.baudrate fn.ft

"option" consists of a single character PRIMARY OPTION,
and 0, 1, or more characters of SECONDARY OPTIONS.

fn.ft is the filename to be received or sent

        PRIMARY OPTIONS:

S:    To send a file
R:    To receive a file
T:    Terminal - i.e. the system being communicated with
    must echo
E:    Terminal mode but with echo - this would be used when 2
    people using the MODEM program are talking keyboard to
    keyboard - one uses MODEM T, the other, MODEM E.
D:    Disconnect the phone (if your MODEM supports this)
H:    Help (prints usage documentation)
X:    Prints usage examples


        SUB-OPTIONS:

Q:    A 'Q' may be appended to either 'S' or 'R' to
    transfer 'quietly' i.e. w/ no console I/O.

    This is for several purposes:  1) if you
    have a slow terminal (such as a tty),
    you must use the Q option;  2) if you are
    using this program on a "remote" CP/M system,
    in which the "remote console" is the same as
    the line for sending a file, then you must use
    MODEM SQ or RQ to suppress the console msgs.


S, R, T, C, (or Q) may be followed by the following
    if your MODEM is capable of supporting these:
    (the program currently supports the PMMI).
    If anyone adds the IDS or HAYES, please
    send me a list of equates and changes.
    (address in MODEM.asm file)

O:    go to originate mode
A:    go to answer mode
D:    disconnect (otherwise, keeps the line)

note 'O' and 'A' are n-o-t defaulted (i.e. send
    to originate), etc.  This is because when
    sending or receiving multiple files with
    the same mode stays in effect (no action
    taken to the MODEM) unless you disconnected
    with a 'D' option, in which case you must
    'O' or 'A'

R:    Show characters as received
S:    Show characters as sent
V:    View the file (suppresses non-error
        status messages)

T:    Go to terminal mode after file transfer
E:    Go to echo mode after file transfer
D:    Disconnect after program execution

        EXAMPLES:

send 'test.fil' in originate mode, 'quietly',
disconnect after transfer

    MODEM SOQD test.fil

receive 'test.fil' in answer mode at 450 baud,
and don't disconnect after.

    MODEM RA.450 test.fil

Suppose you have sent 1 or more files already,
did not 'D' (disconnect) and want to send
or receive another, just:

    MODEM S test.fil

(note this defaults to 300, so s.450 or whatever
if that is the rate you were going at)

After transferring the last file, use the D sub-option
(MODEM SOD.450 name) or re-type the MODEM command with
the D primary option (MODEM D) to disconnect the phone.

------------------------------------------------

In the process of re-writing the MODEM program
for the variable-baud-rate PMMI (and adding the
functions for answer, orig, disconnect, view, etc),
the following "historical" prolog was deleted.
(..and the file was > 32K).  It is reproduced here
to give credit where credit due:


    09/23/77
First written by Ward Christensen

    09/26/77
Add error$limit equ (WLC)

    10/01/77
Change exit$char from ctl-c to ctl-e for use
w/timesharing computers (WLC)

    10/10/77
Correct to send any length file (WLC)

    11/20/78
Change send wait for ack time to 8 sec. for
slower disk systems.  Add control-X abort so
receiving station can stop send.  Add abort
test to send and receive for local cancel.
By Keith Petersen, W8SDZ

    12/03/78
Add 16-sector buffer for less disk activity.  This
version typed by Keith Petersen, from information
supplied by Jim Bell, K4FUP

    01/05/79
Correct error in receive file routine which did
'ACK' when sector number was wrong.  Add wait
routine to hold sending of file until receive end
is ready.  by Keith Petersen, W8SDZ

    02/19/79
Change receive wait time to 8 seconds to allow for
slower disk systems.  Eliminate multiple cancel on
aborting.  Add conditional assembly for clock
frequency > 2.0 mhz. by Keith Petersen

    04/11/79
Change send, receive, and eof ack wait times to
10 seconds to allow for slower disk systems.
Change send wait time to 80 seconds to allow
receiving end more time to come up.  By
Keith Petersen, W8SDZ.

    04/23/79
By Ward Christensen:  put in PMMI variable baud
rate select, originate, answer, quiet, disconnect;
delete sense sw codes;  add view, help, examples,
etc.  Change garbage char collection to "in" instr.
not "recv".  Add quit/retry from 12/78 vers which
Keith didn't have.  Un-do the 1/5/79 correction,
allowing the receiver to ack if a duplicate
block is sent, such as might happen if the
receiver's original ack was garbaged.

    04/25/79
From Keith Petersen W8SDZ: add technique of de-
leting garbage characters to avoid problems with
line glitches.

    04/28/79
By Ward Christensen: re-write program, making it more
structured, and better commented.

END