ISDN is very reliable yielding a 128 kbps symmetric connection. You can save a little by moving your phone to ISDN. ISDN is smart enough to automatically switch between data lines and one when phone is in use. You need to also find a dialup ISP that allow bonding both channels and has local POP access numbers.
Check out the ISDN forum if you have more questions.
»
ISDNThere is a data version called IDSL. Uses ISDN signally but is data only it provides 144 kbps symmetric. Need to check out local Broadband ISPs to see if they support it.
As others have posted Sat has very high latency due to geosynchronous orbit. WISP latency should be much less, just modem processing. Best bet is to contact local WISP and ask.
/tom