Path: utzoo!attcan!uunet!lll-winken!ames!sun-barr!apple!bbn!mailrus!cornell!batcomputer!pwong
From: pwong@batcomputer.tn.cornell.edu (Patrick Wong)
Newsgroups: comp.sys.cbm
Subject: rs-232 interface for c64 (AN UPDATE !!)
Keywords: RS-232,C64,Hayes comp. modem
Message-ID: <7932@batcomputer.tn.cornell.edu>
Date: 12 May 89 14:46:56 GMT
Organization: Theory Center, Cornell U., Ithaca NY
Lines: 37

Hi, guys,

The result is in !  Finally, instead of buying a standard rs-232 interface
for my c64, I bought a "COM-MODEM" adaptor for just under $25 (US) including
shipping.  I use this adaptor to interface between the c64 and a 2400 baud
Hayes comp. modem.  This adaptor is basically a 3"x3" board with the
following components: A DB25 female connector, an edge connector for
the c64 user port, a chip, a switch that allows me to select between
1670 emulation and Hayes, and a ON/Off switch.  The bottom side of
the circuit is coated with a blue stuff (so that no one can find out
the circuitry of this gadget) and the label on the chip has been masked
by a black marker pen.  If I find a safe way to remove the marker ink
in the future, I would gladly tell anyone who wants to know.  For the
coating , that's another story though.....

I have used the above configuration with two communication software:
CCGMS 6.0 and C64KERMIT.  With CCGMS, it works beautifully all the way
up to 2400 baud !!! Though I have not tried up/down load at that
rate.  With KERMIT  , I only have limited success.  KERMIT can allow
work up to 1200 baud.  When I tried to use 2400 baud rate, the
only thing I got on the monitor after connecting with the school
mainframe was a series of control characters - i.e. meaningless stuff !
Some time ago on this group, someone posted something about this, I
believe.  Can those knowledgeable people shed some light on me please ?
It is nice to be able to connect with all the local BBS at 2400 baud
rate and do some up/downloading.  However, my true need is to be able
to use my system and KERMIT to connect with the mainframe to do some
graduate research work while at home.  Please help !!!!

PS -> I did not notice any difference between the Hayes mode and the
      1670 emulation mode on the adaptor while I was using CCGMS.
      Perhaps 1670 is a Hayes comp. device anyway, so there is no
      noticeable difference ! But then why does the manufacturer put
      this switch in ?  I wonder...

                                            Patrick Wong (the novice)
                                             pcw@squid.tn.cornell.edu