[amsat-bb] TH7-D question

[Jim White <jim@xxxxxxxxxxxxxxxxxxxxx>]

Gents,
We are having a frustrating problem getting a pair of TH7-D radios to talk 
to each other in 1200 packet mode.  We are talking across the room, about 
10' apart.  A computer is attached to the serial port on each 
radio.  Radios are in 1200 packet mode with all parms at default. We have 
tried both hardware and software flow mode with the same result.

 From radio A connect to B.  Connect works and they both show 
connected.  CON indicator on the display comes on.
Send a packet in convers mode from A to B.  I can hear the packet send and 
hear B send something in response.  The packet shows up on the screen on 
the PC attached to B.  The STA indicator on the A radio comes on, then goes 
off when the ack packet is received from B.
Send a packet from B to A.  The packet shows up on the A PC.  The STA 
indicator on the A radio display comes on and stays on.

Now we cannot send anything from A to B.  Anything typed from the PC 
keyboard is ignored by the A radio.

Another symptom is if I now reset the A radio (power off/on), the STA 
indicator goes off.  If we send a packet from A to B the response we get on 
the A PC is 'busy', which seems to indicate the B radio is still 
connected.  Yet the connect status on the B radio shows disconnected.  If 
we go to command mode on B and enter disconnect the response is link state 
disconnected.

Another clue may be in the following sequence:
Disconnect the PC from radio B.
Connect from A to B.  The connect works as seen from the A end.
Send a packet from A to B.  Listening on the link I hear A send and B 
respond.  But the STA indicator on A stays on and we anything typed on the 
A PC is ignored by the A radio.

I have a hunch this is related to two things 1) the radios will only allow 
a single packet to be queued, and 2) if the B radio cannot deliver the 
packet to it's attached PC it won't accept another packet from the A 
radio.  The B radio seems to be delivering the packet ok when the PC is 
hooked up but I'm suspicious there may be a flow control issue between the 
B radio and it's PC such that the B radio doesn't recognize the PC got it.

So questions:
Has anyone had this sort of problem and what did you do to fix it?
Is my diagnosis reasonable?
How can it get the B radio to essentially ignore flow control to/from its 
attached PC?
Is it possible to get these radios into unproto mode so I can just 
communicate between them using UI frames?

Jim

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