[Coco] RS-232 Cable

[Bob Devries]

Mark,
You will find that the coco's pin 1 is in fact not used, but is connected to 
either logic 1 or 0 (not sure which, I don't have the schematic handy), 
which may have interfered with the PC end.

A null-modem cable is indeed what is required, and you will find that all 
the connections I suggested will be made by that cable.

25 feet is not usually too long, but it really depends on both the Colour 
computer, and the PC. Some are more sensitive than others to that distance. 
The longer the cable, the higher the voltages that are used *should* be, but 
the Coco end is limited to 5 volts, and some PC serial ports are the same. 
This limits the distance it is capable of transmitting over.

Autoterm is a good choice for terminal programme. I have used it 
successfully. GETerm is also great. For preference, I would use an RS232 pak 
on the Coco, but of course, that's dependant on whether you own one.

BASIC can only send characters to the 4-pin serial port, since it was 
designed primarily for a printer connection. So if you set the baud rate 
correctly in BASIC (POKE 150,XX), and use PRINT #-2,"blah, blah", you should 
see that on the receiving screen. That is however the limit to BASIC's 
capabilities in this area.

Hope it helps,
--
Regards, Bob Devries, Dalby, Queensland, Australia

Isaiah 50:4 The sovereign Lord has given me
the capacity to be his spokesman,
so that I know how to help the weary.

website: http://www.home.gil.com.au/~bdevasl
my blog: http://bdevries.invigorated.org/

----- Original Message ----- 
From: "Mark Mellor" <markmbm at jps.net>
To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
Sent: Sunday, November 12, 2006 11:42 PM
Subject: Re: [Coco] RS-232 Cable


> Bob,
>
> I got it to work with another cable.  I have an original CoCo cable that 
> has
> a DB25 connector on it.  Then I hooked up a null modem, then a DB25 to DB9
> connector, and then a straight RS-232 cable to the PC.  I think the 
> problem
> was pin 1 on the CoCo should go to pin 1 on the DB9 and not pin 4.
>
> Regards,
> Mark
>
> ----- Original Message ----- 
> From: "Mark Mellor" <markmbm at jps.net>
> To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
> Sent: Sunday, November 12, 2006 4:49 AM
> Subject: Re: [Coco] RS-232 Cable
>
>
>> Bob,
>>
>> Thanks for the information.  It still doesn't work but I am probably 
>> doing
>> something wrong.  I am using a 25 feet serial cable.  Could it be too
> long?
>> I am using Autoterm by PXE Computing.  I was able to send and receive AT
>> commands to a Hayes compatible modem (different cable).  I was able to do
> a
>> modem to modem direct connect but it only worked one way for some reason.
>> Is there a way to send and receive via the RS-232 in BASIC (CoCo)?  Or do
>> you have to do it in assembly?
>>
>> Regards,
>> Mark
>>
>> ----- Original Message ----- 
>> From: "Bob Devries" <devries.bob at gmail.com>
>> To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
>> Sent: Sunday, November 12, 2006 3:04 AM
>> Subject: Re: [Coco] RS-232 Cable
>>
>>
>> > Mark, the connections are correct, but, in addition, you need to 
>> > connect
>> > pins 1 and 6 together at the PC end, and 7 and 8 together at the PC 
>> > end.
>> > This is to simulate handshaking which the PC needs.
>> > --
>> > Regards, Bob Devries, Dalby, Queensland, Australia
>> >
>> > Isaiah 50:4 The sovereign Lord has given me
>> > the capacity to be his spokesman,
>> > so that I know how to help the weary.
>> >
>> > website: http://www.home.gil.com.au/~bdevasl
>> > my blog: http://bdevries.invigorated.org/
>> >
>> > ----- Original Message ----- 
>> > From: "Mark Mellor" <markmbm at jps.net>
>> > To: <coco at maltedmedia.com>
>> > Sent: Sunday, November 12, 2006 8:51 PM
>> > Subject: [Coco] RS-232 Cable
>> >
>> >
>> > How do you make a RS-232 cable to connect to a PC?  Here's how I did it
>> (not
>> > working):
>> >
>> > Coco RS-232 pin                        PC RS-232 (DB9 connector) pin
>> > ====================================================
>> > 1 Carrier Detect/Ready          4 Data Terminal Ready
>> > 2 Data In                                      3 Transmit Data
>> > 3 Ground                                     5 Ground
>> > 4 Data Out                                  2 Receive Data
>> >
>> > I then disconnected 1 and 4 thinking maybe they weren't needed.
>> >
>> > Mark Mellor
>> >
>> > -- 
>> > Coco mailing list
>> > Coco at maltedmedia.com
>> > http://five.pairlist.net/mailman/listinfo/coco
>> >
>> >
>> > -- 
>> > Coco mailing list
>> > Coco at maltedmedia.com
>> > http://five.pairlist.net/mailman/listinfo/coco
>>
>>
>> -- 
>> Coco mailing list
>> Coco at maltedmedia.com
>> http://five.pairlist.net/mailman/listinfo/coco
>
>
> -- 
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