[RTTY] 75 Baud ... RigExpert ...

[Richard Ferch]

Comments/answers in-line below.

> Figured I'd start here.
>
> Want to play in 75-baud BARTG tomorrow.  Have a new Rigexpert TI5
> which supports FSK.  The problem is that the TI5 uses different fake
> com ports for PTT and FSK.  It does this by hacking EXTFSK, the DLL
> that comes with MMTTY.

I believe you have stated this backwards. As I read the manual, the TI5 
uses different virtual COM ports for CAT, PTT, Winkey and FSK without 
EXTFSK. I believe the reason RE included the hacked version of EXTFSK 
with the TI5 is to support software that must use the same port for PTT 
and FSK. This is not a problem if you are using the N1MM Logger/MMTTY 
combination, because you can do PTT from N1MM Logger and FSK from MMTTY 
on separate ports, thereby avoiding the need to use EXTFSK.

  And RE didn't hack EXTFSK (as far as I can
> tell - the windows doesn't pop up with the hacked version) to support
> 75 bauds.

As I understand it, the reason EXTFSK doesn't support 75 baud is because 
of unacceptably large (for 75 baud) timing jitter with the method EXTFSK 
uses. EXTFSK is a method of last resort, to be used only if you have no 
alternative. Frankly, if you take a reasonable amount of care with sound 
card settings, I think AFSK is preferable to EXTFSK.
>
> I run N1MM with the MMTTY engine though in this case, I don't know if
> that makes a difference.

Yes - it means you can use the separate ports for PTT and FSK without 
resorting to EXTFSK. If the TI5 driver uses COM3 for CAT, COM4 for PTT, 
COM5 for Winkey and COM6 for FSK, for example, you can configure N1MM 
Logger to use COM3 for radio control, COM4 for PTT on RTS, COM5 for CW 
using the Winkey, and COM6 as the digital port, configured in MMTTY for FSK.
>
> Would it be possible to set the "PTT & FSK" setting in MMTTY to the
> FSK port (COM10 here) and then use the "Radio Command" setting?

No. The radio command (CAT) port is in use by N1MM Logger for radio 
control. MMTTY does not have access to it.

  Or
> are they tied together somehow?

If you are using MMTTY stand-alone, it uses the same port for PTT and 
FSK. Even when run under N1MM Logger, MMTTY will send commands to toggle 
RTS and DTR on its FSK port for PTT, but as I understand it the TI5 will 
simply ignore those commands. You should configure N1MM Logger to 
control PTT using RTS on the TI5's PTT port (RE calls this the 
PTT/CW/SoftFSK port, but the only thing you need to use it for is PTT).

One issue you may run into is the timing of PTT. The transfer of data 
over the USB cable is much faster than the actual transmission, and with 
some setups that can result in PTT turning off before the data has 
finished being transmitted. With any USB-based device, in the MMTTY 
Setup window you should click on the USB Port button beside the 
COM-TxD(FSK) selection under the Misc tab, and select C. Limiting Speed.
>
> And, yes, like my old RigBlaster+, I have to fiddle with a jumper in
> the RE ...  (I haven't ordered the reed switches yet).

In addition to the baud rate jumper in the TI5, you will also have to 
set up MMTTY to receive 75 baud. See 
<http://n1mm.hamdocs.com/tiki-index.php?page=Digital+-+MMTTY+for+RTTY+Support&structure=N1MM+Logger+Documentation#Using_MMTTY_for_75_baud_RTTY> 
for some of the things to look out for.
>
> Anyone encounter this before?
>
> --
> Peter Laws | N5UWY | plaws plaws net | Travel by Train!

73,
Rich VE3KI