[wellylug] DSE Serial Modem Flow Control

[Jamie Dobbs]

> How is a serial modem a winmodem?

Because if offloads the processing of data to the host rather than doing
it themselves. They do indeed exist and it may be that this is one of them
especially given the problems that Jethro is describing.

The only other thing that comes to mind that may cause these sorts of
problems is older serial UARTs with no (or very low) buffer which make it
virtually impossoble to use anything about 2400baud reliably.


>
>
> On 8/02/2005, at 8:05 PM, Jamie Dobbs wrote:
>
>>  That looks like a 'soft' modem (ie. WinModem) style of modem to me.
>> Best to get rid of it and see if you can find anyone that has a "real"
>> modem.
>>
>>  Jethro Carr wrote:
>> On Tue, 2005-02-08 at 22:06, Jamie Dobbs wrote:
>>
>> Make sure you have a fully compliant modem cable and use hardware flow
>> control - soft flow-control is generally crap.
>>
>> I know I have a decent modem cable. I use the one from the box & I also
>> tried the one from my other modem.
>>
>>
>> I've sent an email to DSE support. Maybe they can give me some info.
>>
>> Also, here's what I've found from playing around:
>>
>> I can download anything okay, & upload very small amounts of data (such
>> as a request to view a webpage),but when I want to upload something of
>> common size - such as sending an email, the program will timeout.
>>
>> I've looked this up in google & the Linux Modem & Serial Port HOWTOs,
>> and they say this sort of program can be caused by flow control not
>> working.
>>
>> I looked up the AT command set for this modem in the PDF manual, and it
>> says that the K3 & K4 commands should enable flow control. I tried
>> these
>> AT commands, but they appear to make no effect on the problem. I also
>> tried to change the serial port settings with the stty program, but
>> this
>> didn't work either.
>>
>> The modem lights are like:
>>
>> DISCONNECTED FROM THE WEB:
>> MR = on
>> CTS = on
>>
>> CONNECTED TO THE WEB:
>> MR = on
>> TR = on
>> CD = on
>> SD & RD = on when data transfer is occuring.
>> RTS = on
>> CTS = on
>> OH = off
>>
>>
>>
>> if anyone can help me, it would be great.
>>
>> Does anyone else here have this particular modem? If so, I wouldn't
>> mind
>> seeing what AT commands you use with it.
>>
>>
>> thanks,
>>
>>
>>
>>
>> hi all,
>>
>> I just got a DSE Electronics Serial 56k Modem
>> (
>> http://www.dse.co.nz/cgi-bin/dse.storefront/
>> 4207ba1c0067f898273fc0a87f9906e9/Product/View/XH1142 )
>>
>>
>> It works, except I can't seem to enable flow control. This is a
>> problem,
>> because when I try to upload anything, the modem gets the data sent to
>> it too fast, and drops the packets. This makes it impossible to even
>> send email.
>>
>>
>> Can anyone give me some help here?
>>
>> I've tried using the &K4 command (to enable xon/xoff), but it doesn't
>> appear to do work. :-(
>>
>>
>>
>> thanks,
>>
>> --
>> -- Jethro
>>
>>  dodocaptain at paradise.net.nz
>>  jethro.carr at jedolinux.com
>>
>>  http://www.jedolinux.com
>>  http://homepages.paradise.net.nz/jethroc
>>  http://homepages.paradise.net.nz/jethroc/cv.html
>>
>>  http://www.wellylug.org.nz
>>
>>
>> --
>> Wellington Linux Users Group Mailing List:
>> wellylug at lists.wellylug.org.nz
>> To Leave:  http://lists.wellylug.org.nz/mailman/listinfo/wellylug
>>
>>
>>
>>
>>
>>  No virus found in this outgoing message.
>> Checked by AVG Anti-Virus.
>> Version: 7.0.300 / Virus Database: 265.8.5 - Release Date: 3/02/2005
>