PE> I interpret the V34 spec to say that 64, 32
PE> and 16-state trellis coding are REQUIRED.

RS> Welp, thats a dud interpretation, its not.

Oh yeah.  Read the spec recently?

It says:

9.6.3.2

The encoder shall be selected by the receiving modem during Phase 4
of the start-up procedures specified in 11.4 or 12.4.  The following
encoders ARE AVAILABLE:  

- 16-state
- 32-state
- 64-state

Note that it doesn't use somethings soft like "may be available".

PE> However, it is in the hands of the
PE> answering modem to CHOOSE any one of the 3.

PE> Otherwise, how does the USR know that it is
PE> allowed to ask for 64-state trellis coding or not?

RS> Thats all spelt out in that standard, how a range
RS> of alts is offered and accepted or refused.

Which section would that be in?  Presumably not the bit that says:

29:30 Trellis encoder select bits:
0 = 16 state, 1 = 32 state, 2 = 64 state, 3 = reserved for ITU
Receiver REQUIRES remote-end transmitter to use selected trellis
encoder.

NOTE - Source modem does not use bits 29-32, and should set these
bits to 0.

So Rod, just where does the transmitter get to select maximum
supported trellis-encoding, when it is SPECIFICALLY REQUIRED to
zero out the bits that deal with trellis coding?

BFN.  Paul.
@EOT:

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