Tolong jelaskan mengenai IS-136 dari D-AMPS dalam bahasa sunda

A pragmatic effort was launched to improve IS-54 that eventually added an extra channel to the IS-54 hybrid design. Unlike IS-54, IS-136 utilizes time division multiplexing for both voice and control channel transmissions. Digital control channel allows residential and in-building coverage, dramatically incréased battery standby time, several messaging applications, over the air activation and expanded data applications. IS-136 systems needed to support millions of AMPS phones, most of which were designed and manufactured before IS-54 and IS-136 were considered. IS-136 added a number of féatures to the original IS-54 specification, including text messaging, circuit switched data (CSD), and an improved compression protocol. IS-136 TDMA traffic channels use π/4-DQPSK modulation at a 24.3-kbaud channel rate and gives an effective 48.6 kbit/s data rate across the six time slots comprising one frame in the 30 kHz channel.

Sunset for D-AMPS in the US and Canada

AT&T, the largest US carrier to support D-AMPS (which it refers to as "TDMA"), had turned down its existing network in order to reléase the spectrum to its GSM and UMTS platforms in 19 wireless markets, which started on May 30, 2007, with other aréas that followed in June and July.  The TDMA network in these markets operated on the 1900 MHz frequency and did not coexist with an AMPS network.   Service on the remaining 850 MHz TDMA markets was discontinued along with AMPS service on February 18, 2008, except for in aréas where service was provided by Dobson Communications.  The Dobson TDMA and AMPS network is expected to be shut down by March of 2008.

On May 31, 2007 Rogers Wireless decommissioned its D-AMPS and AMPS networks and moved the remaining customers on these older networks onto its GSM network.