I never found out who—or what—wrote that ghost rung. But every night since, when Syswin 64-bit runs in its compatibility mode sandbox, I watch the HR area. Waiting for bit 1205 to flip again.

A: Syswin uses very timing-sensitive bit-banging on the UART. Many cheap adapters add jitter. Use FTDI-based adapters only.

Syswin 64 Bit Omron Guide

I never found out who—or what—wrote that ghost rung. But every night since, when Syswin 64-bit runs in its compatibility mode sandbox, I watch the HR area. Waiting for bit 1205 to flip again.

A: Syswin uses very timing-sensitive bit-banging on the UART. Many cheap adapters add jitter. Use FTDI-based adapters only.