Mobile radio telephone

Early examples of this technology include: Parallel to Improved Mobile Telephone Service (IMTS) in the US until the rollout of cellular AMPS systems, a competing mobile telephone technology was called Radio Common Carrier (RCC).

The service was provided from the 1960s until the 1980s when cellular AMPS systems made RCC equipment obsolete.

For example, the phone of an Omaha, Nebraska-based RCC service would not be likely to work in Phoenix, Arizona.

At the end of RCC's existence, industry associations were working on a technical standard that would potentially have allowed roaming, and some mobile users had multiple decoders to enable operation with more than one of the common signaling formats (600/1500, 2805, and Reach).

For example, some systems used two-tone sequential paging to alert a mobile or handheld that a wired phone was trying to call them.