Modern transceivers often include computer interfaces that allow operators to control and automate many functions. CAT control and CI-V are two of the most common systems used for this purpose.
While both methods achieve similar results, they work in different ways and offer unique advantages. By understanding their differences, operators can make informed choices about which method best fits their station.
What Is CAT Control
CAT stands for Computer Aided Transceiver. Manufacturers developed this protocol to allow software to communicate directly with the radio. Through CAT control, a computer can change frequency, adjust modes, control filters, and even key the transmitter.
As a result, operators gain far more precision and convenience than manual operation alone. CAT works by sending standardized commands over a serial or USB connection, and the radio responds in real time. Therefore, logging software, contest tools, and digital mode applications can all synchronize instantly with the rig.
How CAT Control Works
CAT relies on a command set defined by the radio manufacturer. For example, a piece of logging software might send a command telling the transceiver to tune to 14.074 MHz in USB mode. The radio interprets that command and immediately makes the change.
In return, the radio can report its current frequency and status back to the software. This two-way communication ensures accurate logging and smooth operation. Moreover, CAT supports advanced functions such as split operation, filter selection, and memory control, depending on the radio’s capability.
What Is CI-V
CI-V is Icom’s proprietary communication protocol designed for computer control of their radios. It operates on a similar principle as CAT but uses a unique implementation that is specific to Icom equipment.
The CI-V system connects the radio to a computer or accessory through a dedicated interface. Commands are sent using a structured format defined by Icom, and the radio executes those commands instantly. Since Icom designed CI-V for their entire product line, it provides consistent control across many of their models.
How CI-V Works
The CI-V system uses a bidirectional communication line that allows multiple radios or devices to share the same bus. Consequently, one computer can control more than one Icom transceiver simultaneously. Each radio on the bus has an address, which ensures that commands reach the correct unit.
For instance, a PC might issue a command to read the current frequency from a specific transceiver, and only that radio will respond. This structure makes CI-V highly flexible in multi-rig stations and contests. Additionally, CI-V supports nearly all of the same functions as CAT, including tuning, mode switching, and memory management.
Comparing CAT Control and CI-V
Although CAT and CI-V serve the same purpose, they differ in scope and design. CAT is a general term used across many brands, while CI-V is exclusive to Icom. CAT may use RS-232, USB, or virtual COM ports, whereas CI-V relies on Icom’s specific communication bus.
Because CAT has become widely adopted, many logging and digital mode programs support it as a universal standard. In contrast, CI-V is optimized for Icom radios and often provides more complete access to radio functions for those models. Therefore, the choice between the two often depends on the equipment in use.
Which One Is Better
Deciding which system is better depends largely on your station setup. If you own only Icom radios, CI-V offers smooth integration and consistent performance. It also simplifies control when you run multiple Icom rigs because they can share the same CI-V bus.
However, if your station includes radios from several different brands, CAT provides a more flexible solution. Most third-party software supports CAT protocols across multiple manufacturers, making it easier to mix and match equipment. As a result, neither system is inherently better overall, but each shines in its intended environment.
Which One Should You Use
If you operate an Icom transceiver, CI-V will likely provide the best experience because it unlocks every feature of the radio. When paired with Icom’s own accessories or control software, CI-V ensures seamless compatibility. On the other hand, if you use radios from Yaesu, Kenwood, or other brands, then CAT becomes the standard choice.
Furthermore, some Icom radios support both CAT and CI-V through their USB ports, giving you flexibility to choose based on the software you prefer. Operators should consider their equipment, operating style, and future station expansion when making this decision.
Practical Uses of CAT and CI-V
Both CAT and CI-V are invaluable for modern operation. Logging software can automatically track your frequency and mode without manual input. Digital mode programs such as FT8 or RTTY depend on CAT or CI-V for smooth transmit and receive transitions.
Remote control software also relies on these systems to give you full access to the radio from another location. In contests, quick frequency changes and mode switching through computer commands save time and reduce errors. Therefore, these control systems are now essential tools for efficient operation.
Final Thoughts
CAT control and CI-V both provide powerful methods to connect radios with computers. While CAT offers broad compatibility across different brands, CI-V delivers optimized control for Icom equipment.
Choosing the right system depends on your station’s needs, but either way, you will gain speed, accuracy, and convenience in your operating. With careful integration, CAT or CI-V can transform your transceiver into a fully automated and highly responsive part of your amateur radio station.