These motors appear to be copies of Yaskawa motors with C-Channel encoders. The Omron manual lists the encoder output signals as A,B, and S. The S channel contains all six of the commutation pulses multiplexed onto just two lines. Our TI-5103 adapter module is required to test them, and demultiplexes the signals back into there six unique channels (H1 - H6).
They list the S signal as being "serial" but we have confirmation this is standard Yaskawa C-Channel formatting. Do take note that the index signals are also multiplexed into the S-Channel. This means that the jumper on the TI-5103 module should be left on.
Please reference the Yaskawa C-channel support article for further details.