[ntp:questions] Adjust serial device speed in ACTS refclock driver?
Brian.Inglis at SystematicSw.ab.ca
Mon Oct 6 08:36:24 UTC 2014
On 2014-10-06 00:57, Rob wrote:
> Rich Wales <richw at richw.org> wrote:
>> Replying to Brian Inglis:
>>> Modem cards would run at whatever interface rate the system set,
>>> e.g. 19,200 or 115,200, and use the remote connect info to set the
>>> line speed.
>> I would normally expect a "sane" modem to act as you described. But
>> this TrendNet TFM-561U appears to be tying the telco line speed to be
>> the same as the system serial port speed.
>>> The NIST ACTS supported range is 1,200-9,600. . . .
>> I have tried connecting manually (via the "cu" command), and if I use
>> any local serial port speed other than 1200 bps, I am completly unable
>> to connect to the NIST ACTS -- the modem noise cycles through several
>> different tones, apparently trying to negotiate a mutually acceptable
>> speed, but eventually it times out and hangs up.
> This depends on your modem and its settings.
> Many modems can communicate with the system at 115.200 baud and still
> use all their available line standards to do the real connect. Other
> modems may use the communication speed as a hint about what line standard
> they should attempt. E.g. when you communicate at 1200 baud, they will
> try to connect using V.22 and when you use 19.200 baud they try V.32.
> Check your modem manual, in the section with all those cryptic ATSxx=yy
All the docs are really install guides.
Maybe better trying something like a USR USB modem with docs and Linux support.
Take care. Thanks, Brian Inglis
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