Serial Tap Pro

Serial Tap Pro incorporates galvanic isolation across all of its serial inputs to ensure superior signal integrity and robust electrical protection, both for the host (PC) and the serial device. Galvanic isolation means that the USB is isolated from all the interfaces, preventing ground loops and protecting against voltage spikes. This design is critical in industrial and debugging environments where varying ground potentials or noisy power conditions can cause data corruption or damage the host. The isolation barriers sit between the transceivers (RS232, RS485/RS422, and UART) and the FPGA core, electrically separating monitored systems from the USB and internal logic domains.

High Baud Rates

Serial Tap Pro is built for high-performance serial analysis and supports significantly higher baud rates. The tap can operate at up to 2.5 Mbps for RS232 and TTL lines, and up to 2 Mbps for RS485. These speeds make it suitable for time-sensitive applications such as high-throughput data acquisition systems or automation interfaces.

Serial Tap Pro captures all serial events with microsecond-precision, including both byte transmissions and asynchronous line state changes, useful for debugging timing-sensitive issues. This level of accuracy allows devs to analyze inter-byte delays, protocol timing, and flow control transitions, and to correlate events across systems with exact timestamps. By preserving both the data and its context, the tap enables detailed reconstruction of sequences, which is essential for troubleshooting, validation, and embedded system development.

Serial Tap Pro supports 9-bit UART communication, a feature essential for certain industrial and embedded systems where extended addressing or control signaling is required. Unlike standard 8-bit UART, 9-bit mode allows each frame to carry an extra bit, which is commonly used to distinguish between data bytes and address bytes. This is particularly useful in multidrop or multipoint serial networks, where a single master communicates with multiple slave devices on the same bus. In such configurations, the 9th bit can serve as an address flag, enabling the master to indicate when a byte is an address rather than data. Slaves then listen for their specific address before processing incoming data. This approach eliminates the need for complex software-level addressing schemes and reduces bus traffic. Applications that benefit from 9-bit UART include RS485 networks, legacy SCADA systems, industrial controllers, and custom protocol implementations in embedded environments.

Serial Tap Pro features RS485 data direction detection, enabling you to precisely identify which device on a RS485 bus is transmitting at any given moment. In typical half-duplex RS485 configurations, all nodes share a single differential pair, which makes determining the origin of a message difficult. Serial Tap Pro addresses this by inserting itself in-line between two physical points on the RS485 bus. It connects to the differential pairs D1+/D1− and D2+/D2−. Acting as a transparent man-in-the-middle, its FPGA core actively forwards data between these two bus segments. This approach ensures that for every byte received, the FPGA knows whether it came from the D1 or D2 side, allowing it to infer the sender's direction without relying on protocol decoding or timing heuristics. Thanks to this method, RS485 data direction detection works at the physical layer, independent of the protocol being used in the session.