Probably just their abbreviation for Spindle/Torch Height Controller cable (it’s function, not a cable type).
From your VFD to spindle you will need a 4 conductor shielded (preferably high flex) cable, probably around 16-18awg. From controller box to VFD will depend on whether you are using rs485 or PWM control, but these will just be a couple pairs of wires (spindle on, spindle clockwise) and another pair (0-10v, for PWM). These can be shielded, but it’s not critical here. The signals are low level, 22awg wire is sufficient.
Your VFD manual should be consulted for exact requirements.
From your VFD to spindle you will need a 4 conductor shielded (preferably high flex) cable, probably around 16-18awg. From controller box to VFD will depend on whether you are using rs485 or PWM control, but these will just be a couple pairs of wires (spindle on, spindle clockwise) and another pair (0-10v, for PWM). These can be shielded, but it’s not critical here. The signals are low level, 22awg wire is sufficient.
Your VFD manual should be consulted for exact requirements.