Re: A new serial baud rate

Re: A new serial baud rate

[henrique]

Hello !!!

After the last e-mails about this issue I've checked the equipment. I am not 
actually dealing with a modem, I'm dealing with a mux/demux which is 
connected to a modem. The demux has 20 ports and 5 of these ports have the
mentioned speed. I have a multi-serial board that uses the UART 16550A.

I plan to make this implementation, firstly using a ioctl as suggested by  
Matti Aarnio, and afterwards changing the termios.h, task that I believe to 
be harder than the first one.

Ed, unfortunately my equipment uses the 2.2.14 kernel. Does your suggestion 
work in such kernel ? It would be the easiest way to solve this.

regards
Henrique

On Thursday 25 July 2002 05:26 pm, Gary Frerking wrote:
> Henrique,
>
> >> That's the problem. I can't change the modem configuration cause this
>
> modem are provided by the Telco. I have to use this baud rate. And I
> wanna use it with Linux. <<
>
> I've never run across a modem that requires a 14400 baud rate on the
> serial line. I *have* run across many, many people *thinking* they need
> 14400 on the serial line because it's a 14400 modem (is this for faxing?
> 14400 often comes up in relation to faxing).
>
> We obviously have no way of knowing more about what you're dealing with
> than what you're able/willing to tell us -- but based on past
> experience, I'm skeptical about the fact that you need 14400 on the
> serial line.
>
> Can you provide more details about the modem itself? Do you have a model
> number? What are you using it for?
>
> -- Gary

-- 
---
Henrique Gobbi
Software Engineer
+55 11 50333339
Cyclades Corporation - The Leader in Linux Connectivity

Re: A new serial baud rate

[henrique]

Hello !!!

FYI, I have done the changes on the kernel to include 14400 bps support. The 
modifications are:

- include/asm-ppc/termbits.h
	- create the define B14400 after B9600 and shift all defines after this.
- drivers/char/tty_io.c
	- add 14400 to baud_table

As you can see, I've done it for a PowerPC. I don't know if it is also quite 
simple for another arch's.

thanks for your feedback
regards
Henrique

On Friday 26 July 2002 01:00 pm, Ed Vance wrote:
> > > On Thu, July 25, 2002 at 12:14 PM, henrique wrote:
> > > > I just wanna know what is the procedure to insert this new baud
> > > > rate (14400) in the linux kernel.
> >
> > On Thu, July 25, 2002 at 2:36 PM, Ed Vance wrote:
> > > If you have a 2.4.x kernel, and your serial ports have "simple"
> > > UARTs like a 16550A, then use the setserial command to directly
> > > set the UART's divisor. See the man page on setserial, which also
> > > has words about how to put the setserial commands into a script
> > > that runs automatically when you boot the system.
> > >
> > > You will have to know the "baud base" rate of your UARTs. This is
> > > the baud rate that you get if you set the divisor to 1 (probably
> > > 115200 bps).
> > >
> > > The new divisor is baud_base / 14400 (which is probably 8).
>
> On Fri, July 26, 2002 at 6:15 AM, henrique wrote:
> > Ed, unfortunately my equipment uses the 2.2.14 kernel.
> > Does your suggestion work in such kernel ? It would be
> > the easiest way to solve this.
>
> Hi Henrique,
>
> I know of no specific reason why it would not work under 2.2. I just
> have no direct experience with the 2.2 kernel and the corresponding
> version of the serial driver. If the setserial functionality that I
> described is in your setserial man page from 2.2, then I think the
> method should work well.
>
> Best regards,
> Ed
>
> ----------------------------------------------------------------
> Ed Vance              edv@macrolink.com
> Macrolink, Inc.       1500 N. Kellogg Dr  Anaheim, CA  92807
> ----------------------------------------------------------------

RE: A new serial baud rate

[Ed Vance]

> > On Thu, July 25, 2002 at 12:14 PM, henrique wrote:
> > > I just wanna know what is the procedure to insert this new baud 
> > > rate (14400) in the linux kernel.
> > > 

> On Thu, July 25, 2002 at 2:36 PM, Ed Vance wrote:
> > If you have a 2.4.x kernel, and your serial ports have "simple" 
> > UARTs like a 16550A, then use the setserial command to directly 
> > set the UART's divisor. See the man page on setserial, which also 
> > has words about how to put the setserial commands into a script 
> > that runs automatically when you boot the system.
> > 
> > You will have to know the "baud base" rate of your UARTs. This is 
> > the baud rate that you get if you set the divisor to 1 (probably 
> > 115200 bps).
> > 
> > The new divisor is baud_base / 14400 (which is probably 8).
> > 

On Fri, July 26, 2002 at 6:15 AM, henrique wrote:
> 
> Ed, unfortunately my equipment uses the 2.2.14 kernel. 
> Does your suggestion work in such kernel ? It would be 
> the easiest way to solve this.
> 

Hi Henrique,

I know of no specific reason why it would not work under 2.2. I just 
have no direct experience with the 2.2 kernel and the corresponding 
version of the serial driver. If the setserial functionality that I 
described is in your setserial man page from 2.2, then I think the 
method should work well. 

Best regards,
Ed

---------------------------------------------------------------- 
Ed Vance              edv@macrolink.com
Macrolink, Inc.       1500 N. Kellogg Dr  Anaheim, CA  92807
----------------------------------------------------------------

RE: A new serial baud rate

[Ed Vance]

> On Thu, July 25, 2002 at 12:14 PM, henrique wrote:
> 
> I just wanna know what is the procedure to insert this new baud rate 
> in the linux kernel.

Hi Henrique,

If you have a 2.4.x kernel, and your serial ports have "simple" UARTs like a
16550A, then use the setserial command to directly set the UART's divisor.
See the man page on setserial, which also has words about how to put the
setserial commands into a script that runs automatically when you boot the
system.

You will have to know the "baud base" rate of your UARTs. This is the baud
rate that you get if you set the divisor to 1 (probably 115200 bps).

The new divisor is baud_base / 14400 (which is probably 8).

Good luck with it!
Ed

---------------------------------------------------------------- 
Ed Vance              edv@macrolink.com
Macrolink, Inc.       1500 N. Kellogg Dr  Anaheim, CA  92807
----------------------------------------------------------------

Re: A new serial baud rate

[Matti Aarnio]

On Thu, Jul 25, 2002 at 04:14:08PM -0300, henrique wrote:
> Hello Gary !!!
> 
> Thanks for your answer. Please see comments no the text.
...
> That's the problem. I can't change the modem configuration cause this modem 
> are provided by the Telco. I have to use this baud rate. And I wanna use it 
> with Linux.

  If the interface is asynchronous, the device will adapt to well-known
  asynchronous baud-rates.  If the interface is SYNCHRONOUS, your hardware
  will be quite special, and it will receive the serial clock from the
  modem  ->  DTE (computer) does not define the speed at all.

  You are not giving details with the modem, and what you have tried
  previously -- e.g. using it with 19200 baud speed, and observing it
  to react on async serial port.

> I just wanna know what is the procedure to insert this new baud rate in
> the linux kernel

  A discussion at this forum, and getting maintainers (Ted Ts'o) 
  attention.

> regards
> Henrique

/Matti Aarnio

RE: A new serial baud rate

[Neil Everton]

Hi,
	I may be wrong here, but 14400 isn't a 'serial' baud rate it's a 'modem'
baud rate.

	I'm not aware that serial ports can port at 14400, they usually run at 9600
or 19200.

	Most modems (unless they are fixed baud) you can talk at speeds other than
the connect speed.

	Also I believe that 14400 is only 9600 with compression !!!

Regards
Neil


-----Original Message-----
From: linux-serial-owner@vger.kernel.org
[mailto:linux-serial-owner@vger.kernel.org]On Behalf Of henrique
Sent: 25 July 2002 20:14
To: Gary Frerking
Cc: linux-serial@vger.kernel.org
Subject: Re: A new serial baud rate


Hello Gary !!!

Thanks for your answer. Please see comments no the text.

> 14400 relates to the baud rate between the modems, not between the PC
> and the modem (the serial port rate). The "B" defines control the serial
> port rate.
>
> If you want to use 14400, set a higher port rate (ie., 19200 or higher)
> and enable flow control.
>
> Obviously, you'll have to set the modem properly as well.

That's the problem. I can't change the modem configuration cause this modem
are provided by the Telco. I have to use this baud rate. And I wanna use it
with Linux.

I just wanna know what is the procedure to insert this new baud rate in the
linux kernel

regards
Henrique

>
> -- Gary
>
> -----Original Message-----
> From: henrique [mailto:henrique@cyclades.com]
> Sent: Thursday, July 25, 2002 12:23 PM
> To: linux-serial@vger.kernel.org
> Subject: A new serial baud rate
>
> Hello !!!
>
> I want to use the 14400 baud rate on a serial port (I have a lot of
> modems
> configured to this baud rate) but the define B14400 doesn't exist. What
> should I do. Is it a matter of simply insert the new define into
> termbits.h ?
>
> thanks in advance
> ---
> Henrique Gobbi
>
> -
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Re: A new serial baud rate

[Matti Aarnio]

On Thu, Jul 25, 2002 at 03:22:49PM -0300, henrique wrote:
> Hello !!!
> 
> I want to use the 14400 baud rate on a serial port (I have a lot of modems 
> configured to this baud rate) but the define B14400 doesn't exist. What 
> should I do. Is it a matter of simply insert the new define into termbits.h ?

  There seem to exist two different approaches to the speed
  parameter.  The classical is to have  Bnnnnn  constant in
  the <termios.h> POSIX tc{get|set}attr().

  Another is to supply the speed, or at least the divisor explicitely.
  This is done via  TIO[GS]SERIAL  ioctl.  See  setserial(8) for more
  pointers.

  Entirely separate issue is that modem speed of 14400 bauds is
  roughly 18000 bauds of async speed, without considering any of
  possible modem link compression effects.  Modems do adapt to
  your computer serial port speed, and to get full modem speed
  bandwidth into use, your modem-computer link speed needs to
  more capacitous, than what the modem can feed into it.

> thanks in advance
> ---
> Henrique Gobbi

/Matti Aarnio

Re: A new serial baud rate

[henrique]

Hello Gary !!!

Thanks for your answer. Please see comments no the text.

> 14400 relates to the baud rate between the modems, not between the PC
> and the modem (the serial port rate). The "B" defines control the serial
> port rate.
>
> If you want to use 14400, set a higher port rate (ie., 19200 or higher)
> and enable flow control.
>
> Obviously, you'll have to set the modem properly as well.

That's the problem. I can't change the modem configuration cause this modem 
are provided by the Telco. I have to use this baud rate. And I wanna use it 
with Linux.

I just wanna know what is the procedure to insert this new baud rate in the 
linux kernel

regards
Henrique

>
> -- Gary
>
> -----Original Message-----
> From: henrique [mailto:henrique@cyclades.com]
> Sent: Thursday, July 25, 2002 12:23 PM
> To: linux-serial@vger.kernel.org
> Subject: A new serial baud rate
>
> Hello !!!
>
> I want to use the 14400 baud rate on a serial port (I have a lot of
> modems
> configured to this baud rate) but the define B14400 doesn't exist. What
> should I do. Is it a matter of simply insert the new define into
> termbits.h ?
>
> thanks in advance
> ---
> Henrique Gobbi
>
> -
> To unsubscribe from this list: send the line "unsubscribe linux-serial"
> in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: A new serial baud rate

[Mike Dresser]

Set your rate to 57600 then.  Except for 2400's that didn't do
compression, generally, you set the rate to the highest the modem will
support.  In this case, either 57600 or 115200, more likely the former.
If that doesn't work, then use 38400.

On Thu, 25 Jul 2002, henrique wrote:

> Hello !!!
>
> I want to use the 14400 baud rate on a serial port (I have a lot of modems
> configured to this baud rate) but the define B14400 doesn't exist. What
> should I do. Is it a matter of simply insert the new define into termbits.h ?
>
> thanks in advance
> ---
> Henrique Gobbi
>
> -
> To unsubscribe from this list: send the line "unsubscribe linux-serial" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>

A new serial baud rate

[henrique]

Hello !!!

I want to use the 14400 baud rate on a serial port (I have a lot of modems 
configured to this baud rate) but the define B14400 doesn't exist. What 
should I do. Is it a matter of simply insert the new define into termbits.h ?

thanks in advance
---
Henrique Gobbi