[time-nuts] Z3815A receiver transplant

[Ed Palmer]

Hi Morris,

You should be able to bridge one of the TTL to RS-232 ports on a MAX232 
onto the line from the Z3815A to the GT-8031.  This will let you capture 
the commands the Z3815A sends by using any terminal program.  Similarly, 
if you bridge onto the line from the GT-8031 to the Z3815A you can 
capture the responses.  I did that while investigating a problem with my 
Z3801A.

Ed

On 1/24/2014 5:17 PM, Morris Odell wrote:
> Hi all,
>
> The Z3815A is working perfectly with the new receiver except for a
> persistent antenna alarm. The new receiver is reporting the antenna is OK
> but it must have a different self-test answer sentence to the old one. The
> self-test is a PFEC sentence, which is proprietary to the manufacturer and
> not part of the standard NMEA protocol. It's responding appropriately to
> self-test requests from the motherboard but obviously there's a difference
> in the answer sentence which reports antenna integrity. I've tested it with
> two different antennas and they both see lots of sats  properly but still
> produce that alarm.
>
> If anyone here has any documentation or manuals for the Furuno GT-74 I would
> be very grateful for copies. If I can find the reason for the persistent
> alarm and it's a difference in the self-test answer, I'll make up a new
> interface with a microcontroller to emulate the old receiver and then it
> will be indistinguishable!
>
> Morris VK3DOC in Melbourne, Australia
>