[RTTY] It felt like MMTTY under N1MM was sending slowly

[Joe Subich, W4TV]

> There is also two other fields on this page.  One is called 
> "Char. Wait" and "Diddle Wait".  Both of these two fields 
> should be set full to the LEFT.

Character wait and Diddle Wait will certainly slow down MTTY. 
"Digital Output" does not as verified by others. 

However, there is one other possibility that does not necessarily 
involve MMTTY.  If the "slow RTTY" station is using a microHAM 
interface and has "strict BPS" enabled, characters will be sent 
every 220 msec instead of every 165 (1.5 stop bit) or 176 (2.0 
stop bits) msec.  This is equivalent to 45 5N4 (4 stop bits) vs. 
45 5N1.5 or 45 5N2.

Strict BPS causes the Eltima virtual serial ports to disable 
the USB buffer and accept/transmit one character at a time. 
Unfortunately, the Eltima code assumes 8N1 parameters and does 
not pay attention to the number of data bits or stop bits when 
the port is opened.

"Strict BPS" is not necessary with the MMTTY engine (if the 
USB port configuration is set to "C: Limiting Speed") or with 
MixW.  However, "Strict BPS" *IS* required with WriteLog when 
using RTTYrite's Sound Board FSK or Stereo Sound Board FSK TU 
types and with other software that uses the serial port driver's 
"characters remaining" status to signal when to drop PTT.  

Another cause of "slow RTTY" may be those interfaces that use 
a parallel output USB interface with a serializer.  In those 
cases the data rate may be fast or slow if the shift register 
clock is not accurate. 

73, 

   ... Joe, W4TV 
 


> -----Original Message-----
> From: rtty-bounces at contesting.com 
> [mailto:rtty-bounces at contesting.com] On Behalf Of k0bx at arrl.net
> Sent: Monday, February 16, 2009 3:10 PM
> To: rtty at contesting.com
> Subject: [RTTY] It felt like MMTTY under N1MM was sending slowly
> 
> 
> MMTTY has a feature that slows down the output rate of the 
> characters send.  This is what the old UT-4's did.  It for 
> slow typest that wanted to get ahead of the buffer.
> 
> In MMTTY plugin, go to options => TX
> 
> There is a thing called "Digital Output".  This should be set 
> to full to the right.  The default is about 80percent.  This 
> will speed up the output to full baud rate.
> 
> There is also two other fields on this page.  One is called 
> "Char. Wait" and "Diddle Wait".  Both of these two fields 
> should be set full to the LEFT.
> 
> I had the same problem with Writelog.
> 
> Joe K0BX
>