Date   : Fri, 13 Sep 1985 00:51:49 GMT
From   : rex ballard <rb%ccivax.uucp@BRL.ARPA>
Subject: Re: BSR controller

> INCORRECT!   The unit from Radio Shack is *NOT* controlled by an RS232
> port!  The unit connects to the  Color Computer's CASSETTE TAPE interface,
> and there is *NO* documentation on how the CoCo communicates with
> the box.  Th link is bi-directional, meaning the controller box
> can download it's contents to the CoCo for updating, and once
> finished, the CoCo uploads the updated information back into the
> controller.  Once the controller has been programmed with events
> it may be disconncted from the CoCo and runs by itself.  I recently
> purchased one of these, and while the software supplied with it
> (in CoCo ROMPack form) is cute (graphic oriented), it's tedious and
> slow to use.  If anyone out there has **ANY** information on how
> this beastie communicates with the  CoCo, I'd really appreciate
> hearing from you.
> 
>
The exact details are available from the CoCo "Service Manual" (the little
green book) at most RS stores.  Unfortunately, the Cassete port is just
an "analogue switch",  The usual format is KC-1200 format.
   |<1>|<-0->|
    _   __      
___| | |  |  |       (the logical 1,0 may be opposite)
     |_|  |__| 

If regular BASIC cassette I/O commands work or there examples of it
in the owners manual, then this will work.  A line reciever can be
built using an op-amp.

They may have used the Cassette Port because of certain hardware advantages.
(Basic can't write to the RS-232 port,only "Dload")

If they wrote their own interface in ML, it's anybody's guess.