Field Guide · protocol

Also known as: Motorola Type II, SmartNet, SmartZone

Motorola Type II is a classic analog trunked-radio family (SmartNet / SmartZone) that pairs a digital control channel with analog FM voice channels. It was the dominant trunking technology for public-safety and business fleets before the migration to digital P25.1

digital control channel (3600 bps) analog FM voice channels (assigned on demand)
Motorola Type II pairs a digital control channel with analog FM voice channels.

Overview

The control channel (a 3600 bps data stream) issues channel grants, pointing radios in a talkgroup to an analog voice frequency. This makes it a trunked system even though the voice itself is analog FM. Each transmitting radio carries a radio ID.

Technical characteristics

Property Value
Access FDMA
Control channel 3600 bps digital
Voice Analog FM
IDs Talkgroups and radio IDs in control data

History

Introduced by Motorola in the 1980s (SmartNet), later extended with multi-site SmartZone, and ubiquitous through the 1990s–2000s.1

Deployment

Many legacy public-safety and commercial systems; steadily replaced by P25, though some remain in service.

Decoding it with GopherTrunk

GopherTrunk decodes the Type II control channel and follows grants to the analog voice channels. See Status.

Sources

  1. Motorola Type II — Wikipedia, for the SmartNet/SmartZone analog trunking family, its digital control channel, and talkgroup/radio-ID signalling.  2

See also