Model 600/620 High Speed Simulcast Paging System

The Zetron High Speed Simulcast Paging System uses timing information from the Global Positioning System (GPS) to synchronize the transmission of digital paging signals to very tight tolerances. This provides the microsecond timing accuracy necessary for high-speed simulcast paging with protocols such as POCSAG and FLEX�.

The system consists of the Model 600 Wireless Data Manager (Source Unit) and multiple (up to 1000) Model 620 Wireless Data Encoders (Destination Units).

Model 600 Wireless Data Manager
The Model 600 accepts TNPP input from up to three TNPP links, efficiently batches the pages with timing information from an attached GPS, and delivers the pages across a link to multiple Model 620 Wireless Data Encoders.

Model 620 Wireless Data Encoder
The Model 620 receives batches of paging data from the Model 600, and encodes the data for POCSAG or FLEX. At the precise time indicated by an attached GPS, the encoded message batch is sent to the transmitter, resulting in synchronous broadcast with other Model 620 controlled transmitters.

The link between the Source and Destination units may be any type (or combination) of link that can reliably transport data. Designed for nonproprietary transmitters, the system is ideal for cost effective build-out of new transmitter sites for public or private paging system operators.

Standard features include encoding for POCSAG (512, 1200 and 2400 baud) and basic FLEX (1600), support for up to 1000 destinations with TNPP routing and zoning capabilities, multi-frequency transmitter control, Trimble Acutime 2000 compatible GPS interface, traditional two-level digital transmitter interface, and multiple user-definable input/output ports. Optional features include enhanced four-level FLEX (3200 and 6400 baud) for the I20 transmitter interface, and support for other GPS devices.

GPS AND SIMULCAST

Critical to simulcast paging is the requirement to synchronize the transmission of paging to very tight tolerances. Every transmitter that can be received by a particular pager must have its transmission exactly in phase with each other. Timing accuracy of within a few microseconds is necessary to assure reliable transmission of the FLEX protocol. Even transmission of information at the speed of light has a delay that must be equalized in simulcast systems. The controller at the transmitter must compensate for delays introduced by different equipment, path distances, modems and other sources of delay. The High Speed Simulcast System does this by using the Global Positioning Service (GPS). GPS is well-known system used to provide accurate location information to users worldwide. Less well-known is its capability to provide extremely accurate timing information as well. By using GPS timing signals, the Destination Unit is able to synchronize the paging data with microsecond accuracy.

Features

STANDARD

• Accepts page input from any TNPP source
• Supports up to 1000 destinations with TNPP routing and zoning capabilities
• Encodes POCSAG (512, 1200 and 2400 baud) and basic FLEX (1600)
• GPS synchronized simulcast with microsecond accuracy
• Trimble Acutime 2000 compatible GPS interface
• Traditional two-level digital transmitter interface
• Multiple user-definable input/output ports

OPTIONAL

• Enhanced four-level FLEX (3200 and 6400 baud) for I20 transmitter interface
• Interface for other GPS devices

Specifications

GENERAL