D-AMPS is a North American 2G digital cellular radio standard that essentially is a digital version of the earlier analogy AMPS specification. D-AMPS operates in the same 800 MHz band as AMPS and the two can coexist in the same network. D-AMPS uses the same 30 kHz bands as AMPS, and supports up to 416 frequency channels per carrier. D-AMPS employs time division duplex (TDD) to subdivide each frequency channel into six time slots, each of which operates at 8 kbps. Each call initially uses two time slots in each direction, for a total of 16 kbps.