Computer aided transceiver
A serial protocol for computer control of amateur radio equipment.
Computer aided transceiver (CAT) is a non-generic serial protocol used by radio amateurs to control a transceiver or receiver from a computer. Traditional radios rely on manual controls like buttons and dials, but advances in electronics have made computer-controlled devices possible. This enables digital modes such as packet radio and simplifies satellite operation by automatically adjusting frequency to account for the Doppler effect. A purpose-built CAT interface connects the transceiver and computer, with a CAT program managing the process. Each radio or controller has unique hardware and features, detailed in its manual.
CAT interfaces can also orient tracking antennas to follow satellites. The interface is hardware that links the PC and radio, communicating via voltage signals, and may use a USB connection. Dedicated CAT software allows the PC to control the radio; changes made through the program—like frequency or mode adjustments—are displayed on the PC screen. With appropriate software, memories storing frequency and mode information in transceivers can be programmed via the CAT interface. On menu-controlled radios, the interface can access and modify menu and sub-menu items.
The functionality of CAT equipment (software and interface) depends on the radio and the software's features. Generally, newer radios offer more CAT functionality. Logging programs that support CAT can pull information from the radio, such as frequency and mode, for contact records. CAT interfaces and programs control frequency and modes remotely but do not receive or transmit over-the-air signals. Dedicated interfaces exist for data mode operations, though a data mode program can share the CAT interface with other programs.
- Protocol type
- non-generic serial protocol
- Primary use
- remotely controlling a transceiver or radio receiver
- Connection types
- purpose-built CAT interface; can use Universal Serial Bus (USB)
- Control scope
- frequency, mode, menu items, memories
- Signal form
- voltages
Lore & Background
Conventional radios are manually controlled using buttons and dials, but advances in electronics have permitted the development of devices that can be controlled by a computer. Each radio or controller has unique hardware and a unique set of features addressed in specific manuals. A CAT interface is a piece of hardware connecting the PC and the radio, allowing the devices to communicate via voltages. The interface can make use of a Universal Serial Bus (USB) connection. Dedicated software (CAT programs) allows a radio to be controlled through the PC; changes made on the radio through user interactions on the CAT program, such as frequency adjustments or mode changes, are generally shown on the PC's screen. Using appropriate software, memories in transceivers that store frequency and mode information can also be programmed through a CAT interface. On menu-controlled radios, a CAT interface can also be used to access and manipulate menu and sub-menu items. The functionality of CAT equipment depends on the radio and the features included in the CAT software; as a rule, more modern radios have more CAT functionality.
Reader's Guide
CAT interfaces and programs are used to remotely control frequency and modes of a radio, not to receive or transmit any over-the-air signals. For data mode operations there exist dedicated interfaces, though it is possible to access the CAT interface through a data mode program such that the interface is shared by both programs. Logging programs that support CAT operation may benefit from the CAT system providing information from the radio relevant to the contact, such as frequency and mode. The protocol's significance lies in enabling automation of tasks like satellite tracking and digital mode operation, where manual frequency changes would be impractical. Its legacy is as a foundational tool for integrating computers with amateur radio equipment, though each manufacturer's implementation remains unique and documented in specific manuals.
Did You Know?
- CAT interfaces can be used to orient tracking antennas to follow the movement of satellites.
- Logging programs that support CAT operation may receive frequency and mode information from the radio.
- More modern radios generally have more CAT functionality.
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