CT2 - Similar Systems

Similar Systems

Japan's Personal Handyphone System, another system based upon microcells, is a direct analog of CT2 and has achieved a much greater level of success. PHS is a full microcellular system, with hand-off, with better range and more features.

The DECT system is CT2's successor, and also supports full microcellular service and data. However, to date DECT has been used to provide commercial mobile-phone like service only in Italy in 1997-8 (the FIDO network).

In the US, a system similar to DECT and PHS called PACS was developed but never deployed commercially.

CT-2, as used in Europe and Hong Kong, required adherence to the MPT 1322 and MPT 1334 technical standards. Most striking was the use of TDD (Time division duplex) channels where only one radio channel was used to carry both sides of a duplex telephone conversation. This solved the problem of different propagation paths between two widely separated channels (up to 45 MHz in some cellular systems), but also placed an upper limit on the range of CT-2 signaling, since the speed of light (and radio signals) prevented long transmission paths. However, the use of TDD made available many frequency bands for CT-2 use, since a "paired" return path was not needed.

An American company, Cellular 21, Inc. (later to become Advanced Cordless Technologies, Inc.) headed by broadcaster Matt Edwards, petitioned the FCC to permit the use of CT-2 technology in the US. ACT built two active test systems which were located in Monticello, NY (outdoor), and outside and inside the South Street Seaport complex in lower Manhattan. The Monticello public field trials used the Timex technology which was incompatible with the trans-European standard, while the South Street Seaport indoor test used equipment from Ferranti, GPT, and Motorola, which at the time manufactured CT-2 equipment for Singapore and Hong Kong markets. GPT and Motorola both provided CT-2 equipment for the Rabbit system rollout in France (GPT handset and charger shown above). All the testing was under an FCC Experimental license. The ACT/Cellular 21 "Petition for Rulemaking" (RM-7152), along with a later petition by Millicom, became the basis of the FCC's PCS initiative (FCC GEN Docket 90-314) which resulted in the allocation of frequencies in the 1.7 to 2.1 GHz band as spectrum expansion for the crowded 800 MHz cellular band. The FCC used the acronym PCS to designate Personal Communications Services, separate and distinct from cellular service which was 800 MHz analog at the time. PCS was to be digital-only, and has progressed through several "generations" (mostly marketing designations) such as G3 and G4.