I'm guessing you're looking at a short loop application ( < 2Kft ). I'm currently using the Silicon Labs Si3210 SLIC. https://www.silabs.com. It has a built in controller for a DC-DC converter to generate the ringing voltage. I also noticed you asked about DTMF decoders in another post, the Si3210 has DTMF detection built-in. It also has a couple of oscillators you can use to generate dial tone and stuff.. Cost about $9 in low qty.
Hi sullybully,
the MT8880C Integrated DTMF Transceiver is not obsolete ;
you can get it from zarink site
h**p://products.zarlink.com/product_profiles/MT8880C.htm