Date   : Mon, 27 Sep 1982 00:56:00-EDT
From   : Frank J Wancho <FJW@Mit-Mc>
Subject: Mainframe MODEM implementations

There are several known variations:

LMODEM in MacLisp by Ed Barton (EB@MC or EB@OZ).  This is the
granddaddy of the mainfame modem implementations and is what we use to
up and download the majority of the files to MC:CPM; over the past two
years.  Unfortunately, it is known to work only on the ITS machines
which run MacLisp... Automatically detects if the user is connected to
the host via TELNET (ARPANET) and makes the appropriate adjustments...

(Source: MC:FJW;LMODEM >)


UMODEM in C by Lauren Weinstein (vortex!lauren@lbl-unix) and Rick Conn
(rconn@BRL) for Unix machines.  Has an option for use via ARPANET, but
not tested in that mode due to brain-damaged NCP which strips user
data of the 8th bit on input...

(Source: MC:CPM;AR43:UMODEM C)


TMODEM in C by Eliot Moss (EBM@XX) and more recently by Rick Conn and
just recently by Ed Barton.  TMODEM is a rewrite of UMODEM for TOPS-20
and TENEX machines.  TMODEM is in limbo and in need of further
debugging at last report.  TMODEM is the only one of this list (other
than LMODEM) known to run via an ARPANET TIP or TAC connection.

(Source: MC:CPM:AR43:TMODEM C - may not be THE latest version)


VMODEM in C by Rick Conn for the VAX under VMS(?) - based on TMODEM.


XMODEM in SAIL by Max Diaz (MMD@SAIL).  XMODEM appears to require
"Control-C capability"...  It does not work via ARPANET (yet).

Source: MC:CPM;AR60:XMODEM SAI and XMODEM SAIMSG)


MODEM in MAC by Bill Westfield (BILLW@SRI-KL).  This MODEM is the best
of the lot for TOPS-20 users at this time.  It does not yet work via
ARPANET (yet).

(Source: MC:CPM;AR60:MDM20 158MAC and MDM20X 48MAC, an "experimental"
version by Ted Shapin (BEC.SHAPIN@USC-ECLC) based on MDM20 158MAC).


FTPS and FTPG in MAC by Aaron Wohl (WOHL@CMU-20C).


And, finally, FMODEM, by Dr. Larry Armijo and myself, written in
FORTRAN IV (for the SEL 32/55) and FORTRAN-77 (for the SEL 32/77).

(Source: MC:FJW;AR4:FMODEM FOR for the 55, and S77MDM FOR for the 77).


If you do anything with any of these, please let their authors know
about it - and me, too.

--Frank