Asterisk does not really come into play here.
any load balance would happen BEFORE asterisk comes in to play
What you are asking is not really load balancing.
You are looking a dynamic allotting of voice channels / data channels
You would be looking at the TELCO for this and the split would be better done by them anyway.
With most of ther telco which sell the T-1 and split out channels for data and phone the end user never really sees it, if only two lines or used then only 128k is used for phones the rest is for INET access.
there are so many ways to break out of telco and go into asterisk it is really a job by job setup.
I have a customer who has a CLEC T-1 any “Phone lines” from them are useless for asterisk as the lag time causes echo to be heard.
I have another which had no problem breaking out some “pots” lines for asterisk to use and we get TOLL call sound.
I can find very few telco’s who will even to you about using the lines for asterisk…u get the HUH…what is that?
I was surpised when I spoke to SCB last week to order more paths on a pots line, the rep ask what I needed them for and I said we have more channels than paths, and she said OH, are you running a server like asterisk?
I said yes, she said “we get alot of that now”.
Surpise surpise…Telco’s catching up.