Motorola Type II SmartZone OmniLink
From The RadioReference Wiki
Type II SmartZone OmniLink provides a broad range of robust system features and utilizes a distributed call processing architecture which links up to four multi-site Type II SmartZone systems together into one seamless network, supporting up to 192 sites. Typical users of SmartZone OmniLink systems include organizations who have vast geographic requirements -- such as electric and gas utilities, and extremely large public safety agencies.
Each Zone in an OmniLink network is considered its own SmartZone network, will have its own unique system id, and is controlled by its own Zone Controller. The Zone Controllers are controlled by the Master Controller. Radios can be permitted or restricted to roam from one Zone to another. The OmniLink infrastructure permits each Zone Controller to communicate and coordinate these roaming actions. (This is similar to cellular networks and roaming onto another carrier's network)