H.100 /H.110

TDM based Computer Telephony (CT) interfaces defined by ECTF, ofter also referred to as CT bus, involving dedicated lines for CLK, FrameSync, and data.

HP

horizontal width dimension (5.08mm)

HPC

FMC allows for two sizes of connector, Low Pin Count (LPC) and High Pin Count (HPC), each offering different (maximum) levels of connectivity. (Wikipedia, FPGA Mezzanine Card)

HPI

Hardware Platform Interface

HPM

Hardware Platform Management

Hz

Hertz