MIDIAN ELECTRONICS: DTMF Equipped Tone Remote Repeater Interoperability Controller.
Midian's RIC-8 is a DTMF equipped tone remote controller. Up to eight RIC-8 units can be connected in parallel or in series over a dedicated line. The tone remote controller equipped with DTMF dialing sends DTMF commands to allow the RIC-8 units and their associated repeaters to interoperate. The RIC-8 is a special tone remote adaptor that generates 2175 Hz keying tone when the radio's COR is present. The 2175 Hz keying tone activates only the radios that have received a DTMF activation code from a DTMF equipped tone remote controller or field radio. All disabled RIC-8 units ignore the 2175 Hz keying tone.
For example if the dispatcher using the TRC in the diagram below wants to talk to users on Repeater 1 and 3, the dispatcher would first send the prefix digits followed by the RIC-8 ID's. If the prefix is programmed as ** and the RIC-8 ID's are 1 and 3, the dispatcher would enter **13 on the DTMF keypad of the TRC. This command would enable Repeaters 1 and 3 and allow the dispatcher to talk to users on both repeaters, as well as users on Repeaters 1 and 3 to talk back to the dispatcher and to units on the other enabled repeater. Users on other connected repeaters would not hear anything because their repeaters are not enabled. Once the conversation is completed sending only the prefix digits again would disable the link. All Repeaters can be controlled simulcast by encoding the prefix digits along with the Simulcast ID (typically DTMF digit 9) (i.e. **9).
In order for a DTMF field radio to establish a link, the user must first enable their RIC-8 and then enable the link with the desired repeater(s). For example if a user on repeater 1 wants to interoperate with Repeaters 3 and 8, the user would first enter **1 then **138. Entering ** only would then terminate the link.
The RIC-8 is used in systems that need interoperability between radios users on different repeaters.
Up to eight RIC-8 units are connected by a dedicated phone line, telemetry link or microwave to key one another. The RIC-8 looks for a COR indication from the repeater to generate the keying tones.