Set path trace byte.
When hwCposFlagJ1Mode is set to j116ByteMode or j164ByteOrNullMode, this variable takes effect.
When hwCposFlagJ1Mode is set to j116ByteMode, this variable is a string up to 15 characters trace byte.
When hwCposFlagJ1Mode is set to j164ByteOrNullMode, this variable is a string up to 64 characters trace byte.