Q. What is SmarTrunk II?
A.The SmarTrunk II Digital Trunking System is a low cost, wireless communications system which supports group dispatch, individual selective calling and telephone interconnect applications. It is widely used for applications below 800 MHz, with over 5,000 systems and 400,000 subscribers in over 90 counties worldwide. By relying on low cost, conventional radio equipment and add-on logic boards, SmarTrunk II is able to offer many advanced features typically found only in higher cost systems.

Q. How does SmarTrunk II differ from other trunking formats?
A. The most recent FCC interpretation of "trunking" found in the new Part 88 rules uses the word "centralized" to described a trunking system which utilizes a dedicated control channel to provide mobile control. Since the SmarTrunk system does not utilize a dedicated control channel, we have chosen to call SmarTrunk II a "decentralized" or "Scan-Based" system. Because there is no central controller required, SmarTrunk II is generally much less expensive than centralized trunking systems.

Q. What is a "Scan Based" system?
A. Unlike centralized systems, scan based systems do not require exclusive RF channels. The channel selection intelligence is located in the mobiles. When a subscriber initiates a call, the mobile unit searches for a clear channel based on the absence of either CTCSS tone or carrier. When a clear channel is located, the mobile unit places a request for service. After validating the subscriber's ID, the channel controller completes the connection and provides a talk path for the duration of the call.

Q. How are incoming calls processed?
A. When the mobile unit is in an idle condition, the receive audio and the PTT functions are disabled. During this time the mobile is scanning for a system signaling tone. When the signaling tone is detected, the mobile stops scanning and listens for the correct digital data pack. When the correct data pack is detected, the receive audio and the PTT function is enabled and normal radio operation begins. At the end of the call the repeater disconnects and the mobiles resume scanning.

Q. What type of signalling format does the SmarTrunk system use?
A. SmarTrunk II is a proprietary BPSK digital signalling format which is not compatible with any other trunking or signalling protocols. As such, it is highly immune to "hackers" and unauthorized system users. Although proprietary, SmarTrunk II is available for a wide range of radio models from ten different radio manufacturers. Therefore, unlike some other trunking formats, you are not "locked in" to a single source for radio infrastructure or subscriber equipment.

Q. What is the average connect time for SmarTrunk calls?
A. The initial connect time is typically one to three seconds, depending on the type of call requested, the number of channels in the system, and the channel availability at the time of request. Radios equipped with our new "Omni" logic boards with "SmartScan" will acquire a channel in less time. Once a channel is acquired, it is held for the duration of the conversation; therefore, subsequent PTT's are instantaneous.

Q. What base station equipment is required for a SmarTrunk system?
A. A typical SmarTrunk channel would consist of the following items:
 

• One SmarTrunk Model ST-853 Station Controller per repeater.

• A VHF of UHF radio repeater per channel

• A Yaesu/Vertex or other suitable station repeater.

• Antenna system - duplexer or combiner depending on the number of SmarTrunk channels. Coaxial cable and connectors as required.

• A power supply for the radio repeaters and the SmarTrunk controllers.

Each controller in the SmarTrunk system is capable of providing all system services.
There is one SmarTrunk ST-853 controller required for each repeater in the system, up to a maximum of 16 channels per system.

Q. What modem do you recommend I use for my SmarTrunk system?
A. An external modem is required to remotely program the ST-853 controllers via a phone line. We recommend either our ST-913 External Modem (which is a complete kit of all items required), or a US Robotics model 33.6KBS external modem with a 25 pin to 9 pin cable. SmarTrunk does not support other makes and models of modems.