Also known as: SmartNet, SmartZone, SmartNet II, OmniLink
SmartNet and its multi-site successor SmartZone are Motorola’s family of analog trunked-radio systems. They carry ordinary FM voice on the traffic channels but coordinate access with a dedicated 3600-baud digital control channel that continuously assigns callers to free frequencies — the hallmark of Motorola Type II trunking.12
Overview
SmartNet is Motorola’s classic single-site trunking product; SmartZone extends it to wide-area operation by networking multiple sites so a subscriber can roam and be tracked across a region, and OmniLink networks several SmartZone systems together. All of them share the same air interface: a fast digital control channel plus analog FM voice. Systems are commonly identified by their Type II signalling, which uses fleet/subfleet talkgroup addressing rather than the older fixed Type I fleetmaps.
Technical characteristics
| Property | Value |
|---|---|
| Control channel | Dedicated, 3600 bps digital |
| Voice | Analog FM |
| Addressing | Type II talkgroups (some legacy Type I) |
| Channel | 25 kHz (also 12.5 kHz refarmed) |
| Bands | VHF, UHF, 700/800/900 MHz |
| Multi-site | SmartZone / OmniLink networking |
| Simulcast | Common on wide-area sites |
Because voice is analog, anyone monitoring a granted frequency hears clear audio unless the system adds separate voice inversion or DES/DVP scrambling. Many wide-area SmartZone systems use simulcast, transmitting the same channel from several towers on one frequency.
History
Motorola introduced SmartNet in the 1980s as an evolution of its earlier trunking, with SmartZone and OmniLink following to serve statewide and metropolitan agencies through the 1990s. These systems carried a large share of US public-safety and business trunked traffic before P25 digital migration, and many remained in service well into the 2000s and beyond.
Deployment
SmartNet, SmartZone, and OmniLink systems were deployed extensively by police, fire, utilities, transit, and large enterprises across North America. Although many agencies have migrated to P25, a substantial number of analog Motorola trunked systems remain on the air, especially for business and secondary users.
Decoding it with GopherTrunk
GopherTrunk can demodulate the 3600-baud control channel and follow Type II grants to tune the analog FM voice channels; the analog voice itself is then straightforward FM audio. Multi-site roaming, banding plans, and simulcast handling vary by system, so the precise level of SmartNet/SmartZone tracking is best confirmed on the Status page. Voice-inversion or DES scrambling is not defeated — GopherTrunk handles clear and known-key traffic only.
Sources
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Motorola Type II — Wikipedia, for the Type II trunking signalling, the 3600-baud control channel, and SmartNet/SmartZone product naming. ↩
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Trunked radio system — Wikipedia, for the control-channel-plus-voice-channel trunking model these systems implement. ↩