[asterisk-users] how to set iaxmodem receiving speed

[Larry Moore]

On 17/05/2012 2:47 PM, gincantalupo wrote:
> Hi Steve,
>
> you are telling me there is no way to set a particular speed on my 
> iaxmodem in order to force the sender speed?
> I have some problems with a customer who gets malformed faxes even if 
> no error occurs. Since I cannot tell the sender to lower its fax 
> speed, my idea is to force my iaxmodem to a lower fixed speed so the 
> sender is oblidged to negotiate at that speed (or lower, of course) 
> without the customer could realize it, at least at first. :)
> There is no ATA in the middle (I'm using it for my tests but my 
> customer does not have any), all faxes are received thru a primary 
> channel to a bunch of iaxmodems. Sometimes some faxes are corrupted, 
> that's why I thought to lower the speed. I could try to disable ECM 
> but that's even harder to do (found nothing on internet).
>

Hi Giorgio,

You may want to try these settings to set the most basic form of 
transmission on your receiving modems, I would however have thought, ECM 
being on would be better for you as it could then deal with lost frames.

Class1MRSupport:        no
Class1MMRSupport:       no
Class1ECMSupport:       no

To set the ECM frame size to a lower value than the default of 64, you 
would set the following

Class1PersistentECM:    yes
Class1ECMFrameSize:     64

Perhaps the corruption is occurring at the senders end before the data 
is pushed through the modem.

Cheers,

Larry.