Re: [hylafax-users] What is ^Q ^S in xonxoff?

[Dmitry Bely <dbely@mail.ru>]

Giulio Orsero <giulioo@tiscalinet.it> writes:

> Fax-modem data:
> TP560 Data/Fax/Voice 56K Modem
> External Controller Ver1.20, CheckSum=28FC
> DSP Ver1.10 CheckSum=7962
> Controller Ver1.20 Date:Apr 07 10:06
> 
> I could certainly use rtscts instead of xonxoff, but it seems that
> xonxoff is more reliable with certain old fax machines.

Many fax modems do not implement rtscts flow control (according to the
standard it's optional), but yes, software flow control is always
implemented and is enough for all purposes (unless you use adaptive
fax/data answer).

> What do ^Q and ^S mean? The fax is sent ok.

They are ASCII XON and XOFF chars itself :-) Strange enough, that they are
visible -- they have to be intercepted by serial port driver, if it really
configured to use software flow control. Possibly your Hylafax config is
wrong -- modem uses software flow control, but Hylafax/serial port driver
expects hardware one. It's hard to say more -- tracing level is not
adequate.

> Aug 09 09:03:33.61: [11352]: SEND training at v.17 14400 bit/s
> Aug 09 09:03:33.61: [11352]: <-- [9:AT+FTH=3\r]
> Aug 09 09:03:33.66: [11352]: --> [7:CONNECT]
> Aug 09 09:03:33.66: [11352]: <-- data [23]
> Aug 09 09:03:33.66: [11352]: <-- data [2]
> Aug 09 09:03:33.68: [11352]: --> [1:^Q]
> Aug 09 09:03:33.69: [11352]: --> [7:CONNECT]
> Aug 09 09:03:33.69: [11352]: <-- data [6]
> Aug 09 09:03:33.69: [11352]: <-- data [2]
> ...
> Aug 09 09:03:40.62: [11352]: --> [2:OK]
> Aug 09 09:03:40.62: [11352]: TRAINING succeeded
> Aug 09 09:03:40.62: [11352]: <-- [11:AT+FTM=146\r]
> Aug 09 09:03:41.12: [11352]: --> [1:^S]
> Aug 09 09:03:41.12: [11352]: --> [7:CONNECT]
> Aug 09 09:03:41.12: [11352]: SEND begin page
> Aug 09 09:03:41.12: [11352]: <-- data [1026]
> ...
> Aug 09 09:03:42.74: [11352]: SEND send EOP (no more pages or documents)
> Aug 09 09:03:42.74: [11352]: <-- [9:AT+FTH=3\r]
> Aug 09 09:03:42.79: [11352]: --> [7:CONNECT]
> Aug 09 09:03:42.79: [11352]: <-- data [3]
> Aug 09 09:03:42.79: [11352]: <-- data [2]
> Aug 09 09:03:44.11: [11352]: --> [1:^Q]
> Aug 09 09:03:44.11: [11352]: --> [2:OK]
> Aug 09 09:03:44.11: [11352]: <-- [9:AT+FRH=3\r]
> 
> 
> I use the same config file for class-1-xonxoff  with another modem and
> it does not print ^Q ^S sending the same data to the same remote fax
> machine.
> The "good" modem-fax is
> RCV56DPF L8570A Rev 45.0/45.0
> V2010-K56_DLS
> a007840284C6002F
> bC60000000
> r1005111151012000
> r3000111170000000

Hope to hear from you soon,
Dmitry




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