Do you have an analyzer which can measure TTL, 500Kbps, ASYNC, half-duplex (not RS-232C but serial communications of TTL)?
It is possible by using LE-8200A/LE-8200 with OP-SB85L (option).
It is possible by using LE-3500/LE-2500/LE-1500 with OP-SB5G (option).
It is possible by using LE-200PS/LE-150PS with OP-5M (option).