PassPort Trunking

Dispatch Networking and a Whole Lot More
A radio dispatcher is in charge of service technicians widely scattered among 10 counties covering nearly half a state. When the dispatcher radios the technicians, the call, made over a 15-site networked trunked radio system, is heard simultaneously by every radio in the fleet. Later, a service technician makes a call trying to locate a part he knows must be on one of the trucks in the fleet. His call is heard by all the radios in the talk group, even though they are on 12 different sites in the radio network and spread over an area far too wide to be covered by any one tower site. Each networked dispatch radio call is set up in less than half a second and is completed automatically without any end-user interface. As vehicles move among areas of coverage of the various network sites, they seamlessly register onto each new site, and the network is continually updated on the location of every radio in each talk group.

Reliable and efficient Wide Area dispatch Networking, as described in the preceding paragraph, has been the missing technology offering for SMR trunked radio system operators since the infancy of trunking. Many SMR operators have multiple sites with very large coverage footprints. Others have wanted to work with operators having complimentary coverage areas. However, end users could not easily take advantage of this large coverage footprint for dispatch purposes because the sites were not networked together allowing radios on various sites to be part of the same dispatch conversation.

PassPort is . . .
. . . an enhanced low speed trunking protocol that improves on the many shortcomings of the widely  accepted and popular LTR trunking protocol. While LTR met the needs of many early trunking applications, its limitations became very apparent to those wanting to grow their systems beyond the most basic of SMR offerings. Wireless users demand more features, coverage and services from today’s wireless provider. Networking of multiple sites is an important element in the feature mix necessary to meet the needs of today’s wireless customer.

LTR has a severely limited ID code structure and no inherent provision for unique IDs on a per-radio basis. Additionally, there is no protocol specific support for roaming or networking. These basic shortcomings have led to numerous stop-gap efforts to improve and enhance the functionality of LTR systems, but none have adequately addressed the fundamental requirement of many operators to provide Wide-Area Dispatch Networking and seamless roaming between sites. PassPort is the trunking protocol that builds on the most desirable elements of LTR and addresses the needs of radio users with wide area dispatch networking, seamless roaming, selective call capability, positive system management and access control, short message service, voice mail capability and many other enhanced features.

Smart Dispatch
PassPort protocol radios take advantage of Trident’s Smart Dispatch networking mode. In Smart Dispatch, only those sites in the network with mobiles from the in use talk group logged onto them, are used during a dispatch call. This makes the most efficient use of the available spectrum in the network by bringing up the minimum number of channels needed to complete the call to each mobile in the talk group.

PassPort Network Security
To eliminate the problem of piracy and airtime theft, every PassPort mobile radio contains an imbedded ESN (Electronic Serial Number). This ESN cannot be modified in the field by the dealer or the end user.  Every time a radio registers onto a site the ESN is validated. Every time a radio transmits on the network, it sends a unique MIN (Mobile Identity Number). These multiple levels of identifying and tracking every radio in a network provide a high level of system security and protection against fraud.

All PassPort protocol radios receive direct frequency assignment from the network. This eliminates the requirement to program every channel in the network into the radio. As channels and sites are added to the network, there is no need to re-program radios as is required on other trunking protocols.

The PassPort trunking protocol is the missing element for trunking operators seeking to build capable and competitive wireless networks using proven, and often already installed analog radio technology. Using the NTS all digital trunking infrastructure, an operator may continue to provide service to existing end users while adding PassPort radios for customers desiring automatic roaming and other enhanced features. Migration for a channel, system or entire network from analog to digital RF is accomplished by simply changing cards in the NTS system. With PassPort and NTS the future of trunking is here with readily available subscriber units and network infrastructure.