Russell Bryant has post details of a new timing API for Asterisk:

Starting with Asterisk 1.6.1, you will no longer need DAHDI installed at all to get proper timing in Asterisk. There is a new timing API, and there are already two implementations. There is a DAHDI timing interface (res_timing_dahdi) and another (res_timing_pthread) that has no […]

Due to copyright infringements, DAHDI is now the name for the Zaptel channel interface to Asterisk. There was some initial confusion in the Asterisk developer community due to some code being checked in containing ‘DAHDI’ as its name.
Digium has officially announced the zaptel name change to DAHDI.