[Asterisk-Users] Data over Voice through Asterisk

[Kevin P. Fleming]

Andrew Yager wrote:

> Hi,
> 
> I'm trying to make a dialup internet connection through my asterisk PBX. 
> When I bipass the Asterisk box, I can get 51600bps. When I run through 
> the asterisk box, I'm limited to about 21600bps.

Modem connections over 33.6K require that there be only a single 
analog-digital conversion in the path between the ISP's modem and your 
modem. With Asterisk in the middle, you are converting the signal back 
to digital, and then to analog again. You will not be able to go above 
33.6K with Asterisk in between, unless you get digital phone service 
from your telco.