From: James Bradford <sup8pdct@mail.cth.com.au>
To: atari8-l@zwieracz.ideefixe.nom.pl <atari8-l@zwieracz.ideefixe.nom.pl>
Subject: Sio speeds.
Date: Tuesday, April 27, 1999 6:10 AM


I have seen and heard several people/programs that seem to to a bit confused about 
SIO baud rates and which drives have the fastest baud rate.
I have been playing around with my frequency counter which I will admit isen't accuret 
but it gives a good idea of what the baud rate is.
I have also found bits of information on other 1050 drive upgrades and have formed a 
table of sio speeds for varous drives and approxamet baud rates for a PAL system.
This table will be broken into two coloums. The first number is the Hex value placed 
into the pokey audio frequency for the command frame. the second is for the data 
frame.

Cmd		data
$28		$28	19120	 	std rate for all devices except cassette
$28		$10	39000		STD XF551 high speed.
$0A		$0A	52000		USD and compatiables. Happy?
$09		$09	57000		Speedy
$28		$06	72000		IndusGT Syncromesh high speed.

Both XF551 and Indus have  the high bit (7) set of the command byte for a highspeed 
data frame.

I would like to hear from anybody who can add to this or dispute the numbers I have 
come up with. Someone with a better frequency counter can make the baudrates more 
accurate.
The hex table except for the speedy part came from SDX.

Of course, having the Fastest baud rate doesn't make the drive the fastest overall.

James.