There are many used 1st Gen Adtran Total Access 900 Series Gateways out there at much lower prices than the 2nd Gen.
I was curious if there are major differences between the two units.
After some research I found the following:
|Feature||1st Gen||2nd Gen|
|3 Way Conferences via FXS users||0||3|
|Max TDM to IP Call||24||30|
|Max T.38 Sessions||1||4|
|Echo-tail Length||16 ms||64 ms|
Based upon Echo-tail length increased to 64ms and the increased number of T.38 faxes I stick to the the 2ng Gen Gateways.