siegel@stsci.EDU (Howard Siegel) (06/11/91)
On the T1600 there is a register (S59) which enables the suffixes on the
CONNECT message. The documentation for the registers says that the default
value is 0 and the register can have any value in the range 0 to 15. But
there is no further explanation of what the values mean.
The format of the connect message is:
CONNECT (X cmd speed)/(link)/(compression)/(other speed)
where the value in parens is filled in and the slashes separate the
various values.
<Speculation mode on>
There are thus 4 suffix fields in the connect message. The maximum value
for S59 is 15 decimal or F hex, which is 4 bits! So the S59 value appears
to be a bit mask of which suffix fields to include in the message.
Is this correct?
--
Howard Siegel siegel@stsci.edu 301-338-5415
TRW c/o Space Telescope Science Institute Baltimore MD 21218gandrews@netcom.COM (Greg Andrews) (06/11/91)
In article <2744@stsci.EDU> siegel@stsci.EDU (Howard Siegel) writes: >On the T1600 there is a register (S59) which enables the suffixes on the >CONNECT message. The documentation for the registers says that the default >value is 0 and the register can have any value in the range 0 to 15. But >there is no further explanation of what the values mean. > >The format of the connect message is: > > CONNECT (X cmd speed)/(link)/(compression)/(other speed) > >where the value in parens is filled in and the slashes separate the >various values. > ><Speculation mode on> > >There are thus 4 suffix fields in the connect message. The maximum value >for S59 is 15 decimal or F hex, which is 4 bits! So the S59 value appears >to be a bit mask of which suffix fields to include in the message. > >Is this correct? > For the most part, yes, but you forgot about Protocol Support. The "X cmd speed" field is not enabled/disabled by S59. Otherwise the default S59=0 would never give you a speed in the connect message! The third item is which file transfer protocol the modem will support. The true meanings of the fields are: CONNECT XXXX/<Error Control>/<Compression>/<Protocol>/<Other Speed> 1 2 4 8 The numbers under the fields indicate the decimal value to turn on that field's bit in S59. To turn on the bits for the parts you want to see, add up the decimal numbers and set S59 to that decimal value. S59=3 turns on a set of suffixes that match the majority of modems out there - just the modulation speed, error control, and data compression. S59=7 would show everything except the "other" speed, and S59=15 turns on the whole ball of wax. Unfortunately, the manual was already at the printer when somebody noticed that S59 was missing some important info! > Howard Siegel siegel@stsci.edu 301-338-5415 -- .------------------------------------------------------------------------. | Greg Andrews | UUCP: {apple,amdahl,claris}!netcom!gandrews | | | Internet: gandrews@netcom.COM | `------------------------------------------------------------------------'
siegel@stsci.EDU (Howard Siegel) (06/12/91)
In <1991Jun11.025646.8119@netcom.COM>, gandrews@netcom.COM writes: > In article <2744@stsci.EDU> siegel@stsci.EDU (Howard Siegel) writes: > >The format of the connect message is: > > > > CONNECT (X cmd speed)/(link)/(compression)/(other speed) > > For the most part, yes, but you forgot about Protocol Support. The "X cmd > speed" field is not enabled/disabled by S59. Otherwise the default S59=0 > would never give you a speed in the connect message! Actually Telebit forgot the Protocol Support field. The line I typed in comes straight from the T1600 manual (#90156-01 rev A, Appendix C, page 3). The following page gives the list of link suffixes (nothing, REL, LAPM), compression suffixes (nothing, COMP), and other speed suffixes (...). > Unfortunately, the manual was already at the printer when somebody noticed > that S59 was missing some important info! So the manual is both incomplete and incorrect. Par for the course in technical documentation these days. Other than that, it's a real nice modem! -- Howard Siegel siegel@stsci.edu 301-338-5415 TRW c/o Space Telescope Science Institute Baltimore MD 21218