GE Marc V - How IT Worked

How It Worked

In a GE Marc V system:

• electronics that determine which channel a conversation will occur on are inside each radio. Radios scan all available channels in the system to find an unused channel for a conversation. They also scan to look for a tone sequence initiating a conversation from another radio in their own group.
• repeaters are essentially stand-alone repeaters, except for tone handshaking electronics, deadbeat disable computer, telephone patch equipment, or equipment used to bill air time, (talking time). Some of these were options.
• because call set up was slower than transmission-trunked systems, repeaters had a long hang time in order to hold a group's mobile radios on a channel until a conversation was finished. This conversation trunking was the primary difference between Ge Marc V and other systems.
• a trunked system or area could have up to 20 channels. Some 100-channel models, for example, could accommodate five 20-channel areas.
• the user would hear a low-pitched error tone if they took the microphone off hook and no channels were available or the radio was out-of-range.