[Premium-Rx] Racal A6A1 Board Setup Help Needed

[Chuck Hutton]

Hi Guy:

Since you're still stuck with this, I'm toss out any ideas I can think of at
this point...

(1) I know you turned off handshaking at the PC end of the link, but do you
know for sure that the RACAL does not need some handshaking? Does the RACAL
pinout mention CTS or DTR?

(2) Two stop bits would be very, very unusual at 9600 or 19200. In fact, I
have never seen 2 stop bits used at those rates. They were used only at 300
Baud and below, if my fading memory can be trusted.

(3) Since you have manuals, can you get access to the TTL signals after /
before RS232 level translation so that the cable and gender assumptions can
be proven?

(4) I see that the GM-3 manual says "a parity bit". Do they say if it is odd
or even? Some old systems even used two other forms of parity, one of which
was called stick parity and the other match parity if I recall correctly.

(5) I don't know the RACAL RS232 format, but will assume that the address
you mentioned is used to compare against an address field in the 232
message. Do you know exactly what format the address should use in the
message? BCD? Binary? ASCII? Two hex digits, one for each character?

(6) Do you know that the RACAL message format is supported by Hyperterminal?
In other words, does Hyperterminal allow you to transmit any binary value?
Maybe RACAL does not need binary values - it could be pure ASCII - but I
have not a clue.



Sorry to be shotguning suggestions. I'm sure you've crossed many of these
bridges already. Were it me, I'd throw a scope on it and see what the
hardware is doing.


Chuck Hutton


-----Original Message-----
From: premium-rx-bounces at ml.skirrow.org
[mailto:premium-rx-bounces at ml.skirrow.org] On Behalf Of Guy Atkins
Sent: Sunday, February 22, 2004 9:48 PM
To: premium-rx at ml.skirrow.org
Subject: RE: [Premium-Rx] Racal A6A1 Board Setup Help Needed


Hi Claus,

Thanks for taking the time to look up this information. I knew that my
receiver has the GM CPU board with the 3 EPROMs, and I just verified that
the remote board is also a GM model with the IM6402 UART.

So, I have the correct combination of boards, but unfortunately my manuals
cover the GM-3 version.

Could you tell me what your GM manual says is the normal serial protocol? Is
it the common 8-N-1, or maybe "1 start bit, 7 data bits, a parity bit, and 2
stop bits" such as the GM-3 manual states?

Thank you,

Guy

-----Original Message-----
From: Claus Hanke [mailto:claushanke at yahoo.com]
Sent: Sunday, February 22, 2004 9:28 PM
To: Guy Atkins
Cc: Premium-Rx
Subject: Re: [Premium-Rx] Racal A6A1 Board Setup Help Needed


Hi Guy,
I checked both manuals, GM and GM-3, and it is not possible to mix the
boards. So, if you have a remote for the GM-3 (UART 8251) you cannot use it
with the GM CPU board (3 EPROMs and 3850 CPU). The pining between the boards
used by the GM and GM-3 versions are different. The GM-3 CPU is a Z80 (1
EPROM). The UART on the GM remote board is a IM6402 or compatible. That
would explain that the receiver is not working anymore. Pin 2 - GM is the
RESET (active low) and MI (active low) for GM-3. I'm just guessing, but
maybe the CPU is always in RESET mode. Anyhow the two versions are not
compatible, so check what versions you have. Hope that helps. Claus




_______________________________________________

Premium-Rx Mailing List
To Post: premium-rx at ml.skirrow.org
For Info: http://ml.islandnet.com/mailman/listinfo/premium-rx
Visit the Website: http://kahuna.sdsu.edu/~mechtron/PremRxPage/