It really depends how you interpret the NMRA RPs. Continued below.

> According to the NMRA site this is RP 9.2.3. I have
> "sic----Acknowledgment of either bit verify indicates that the
decoder
> fully supports all modes of Direct Configuration Variable
Addressing
> (Verify
> Byte, Write Byte, & Bit Manipulation). A Command Station,
Programmer, or
> Decoder, which supports Direct Mode, must implement all three
> instruction-types."

That's quite clear.

>
> The SPROG said that Blue line does not conform to the NMRA RP and
he is
> right BUT neither does the SPROG as the last sentence says a
command
> station
> (which the SPROG is) MUST implement all three instruction-types
(referring
> to Direct Mode). It appears that the SPROG does not implement
Verify Byte
> and Write Byte instructions or else it would work with the Blue
line.

SPROG DOES implement verify byte. In fact, SPROG uses a combination
of bit and byte modes to implement a fast, robust algorithm for
reading and writing CVs. There is nothing in the RP that states a
command station must use ONLY direct byte or ONLY direct bit to
access a decoder. Turning it around, if the decoder were conformant
there would be problem as, indeed , there is no problem with 99% of
decoders.

> There are some got ya's here. It says to determine if the decoder
supports Direct
> Mode you write to the decoder using "Direct Bit" which, for
example, NCE
> does. Then you must manually tell the NCE system to use Direct as it
> doesn't get an answer from it's write.

The test failed, therefore the decoder does not support direct mode.

> This is also what SPROG does but apparently you can't manually put
SPROG

No, SPROG doesn't do this test. With tools such as JMRI, this test is
redundant since the decoders capabilities are defined by the xml
definition. It's only really of use in command stations that have no
a priori knowledge of the decoder. If the test fails then you should
drop back to paged mode. The Blueline is deficient again as it does
not support page mode.

If the test passes then the command station can assume the decoder
fully supports ALL direct modes (bit and byte).

Andrew