From: William Levak (wlevak_at_cyberspace.org)
Date: 2004-02-15 06:31:30
On Sat, 14 Feb 2004, The Doctor wrote:
> On Sat, Feb 14, 2004 at 02:38:50AM -0500, William Levak wrote:
>
> > I was not able to determine how many "S" registers there are in the 1670.
> > It responds to register numbers from 0 to at least 999999, but there
> > could not possibly be that many registers.
>
> Perhaps they wrap around at some point - register X is treated the same
> as register 0, and so on and so on. I do not know if this is so, but it
> might be instructive to write a short terminal programme script to push
> a value into a register and compare it to a value in a known register to
> see if there is indeed a wraparound.
I tried that with the first 40 registers, but did not see a wraparound
(the 14.4K Hayes modem has only 39 registers). I notice that the ATIn
command responds to any value of n, ATI0 gives the model number, ATI1
gives the ROM checksum, and all other numbers repeat the checksum. It
does not give an "ERROR" as most other modems do. It looks as though the
modem does not have very much error checking on the commands. It's
possible that invalid values for register number are accessing other
memory locations that change, and therefore do not give a pattern.
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