Is there any protocol analyzer that can monitor RS-232C, RS-422 (1Mbps) and RS-485 (4Mbps)?
If RS-485 is normally half-duplex communications, LE-8200A/LE-8200 is an applicable product.
<Speed setting supported at half-duplex>
LE-1500 : up to 500Kbps
LE-2500 : up to 1Mbps
LE-3500 : up to 2Mbps
LE-8200A/LE-8200 : up to 4Mbps
<Speed setting supported at half-duplex>
LE-1500 : up to 500Kbps
LE-2500 : up to 1Mbps
LE-3500 : up to 2Mbps
LE-8200A/LE-8200 : up to 4Mbps