whoo! The 700 series router is an ooooooold, 'special' kinda router. (non-IOS) I haven't configured one of these in, like, 4 years. (then when I did do a couple of these, it was just that - a couple)
Arnotheron, I'll have to see if I have some old documentation at work. The 770 is the one with the additional pots ports on the back, no? If so, it might be easier just to purchase a cisco 804 (it's a fully powered soho ios router with an isdn bri interface and 4 port switch - also includes a couple of pots ports on the back).
See if I can dig something up tomorrow.