Digital Advanced Mobile Phone System (D-AMPS), also known as IS-54 and IS-136, is a second generation (2G) mobile phone system standard. D-AMPS, which is a development of the 1G standard analog AMPS, was able to facilitate a smooth transition from AMPS by using existing channels and bands.
D-AMPS uses π/4 DQPSKDifferential Quadrature Phase-Shift Keying modulation. The same FDMAFrequency Division Multiple Access channeling used in AMPS is used in D-AMPS; however, each 30 kHzKiloHertz (kHz) 10^3 Hz channel is divided into three time slots with TDMATime Division Multiple Access, allowing 3 users per carrier, increasing the number of possible users on the system.
IS-136 is a development of IS-54 which adds an additional TDMATime Division Multiple Access digital control channel (DCCH) which uses π/4 DQPSKDifferential Quadrature Phase-Shift Keying, contrary to FSKFrequency-Shift Keying used in the control channel in IS-54 and analog AMPS. Additionally, IS-136 includes other features including security and SMS.
- IS-136 information
- IS-54 and IS-136
- Details on D-AMPS standards
- Privateline Digital AMPS Basics (Archived Website)
- Telephone World - The First Digital Cellular Systems