Re: Strange ALDL Blather

["Andrew K. Mattei" <amattei@mindspring.com>]

>This clears things up some.  I actually lucked out.  Turns out the 3.1
>protocol is the same as the 3.4 - which is completely detailed in FreeScan.
>I'm still confused about the SumCheck part, however.  Am I supposed to know
>the checksum of the stream before I get it?  So I want to send it F4 57 01
>64 what?


Actually, with a 64 I doubt you'd get anything. You're best trying the 00
(Mode 0) message... See ECMguy's page, good call, Bruce.

F4 57 01 00 CS

Where CS is calculated:

Go to Win95 Calculator. Set to Scientific mode. Then click on the Hex and
Byte radio buttons. Then just do:

F4+56+01+00 =

and then hit the NOT button.

Then add 1 to the result. So in this case, the checksum is B5. Send F4 57 01
00 B5 to the ECM to get the Mode 0 data request. :)

That's the checksum. You must know that on messages you're transmitting, but
on messages you're receiving, unless you're concerned about a noisy ALDL
line, you can usually *assume* they're OK.

HTH,

Andrew

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