Microcom AX/9600 Plus MNP Class 6 External Modem 9600 Baud RS-232 Serial

Microcom AX/9600 Plus MNP Class 6 External Modem 9600 Baud RS-232 Serial

The Microcom AX/9600 Plus is a 9600 baud external dial-up modem supporting MNP Class 6 error correction and data compression. It connects to a host computer via a DB-25 RS-232 serial port and to a standard telephone line via RJ-11 jacks. Manufactured by Microcom Inc. of Norwood, Massachusetts — the company that developed the MNP (Microcom Networking Protocol) standard — this modem predates the V.32 and V.34 ITU standards that later became universal.

Specifications & What's Included

• Manufacturer: Microcom Inc., Norwood, MA USA
• Model: AX/9600 Plus (Model AX)
• Data Rate: 9600 baud (9600 bps)
• Error Correction / Compression Protocol: MNP Class 6
• Host Interface: DB-25 RS-232 serial port (rear panel)
• Telephone Interface: 2x RJ-11 jacks (line in / phone pass-through)
• Power Requirement: 19 VAC, 0.80A, 60 Hz — proprietary power connector
• Front-Panel LEDs: PWR, TST, OH, HS, DTR, TXD, RXD
• Front-Panel Switch: T/D toggle
• Rear Panel: DB-25 serial port, DIP switch block, power jack, reset button, 2x RJ-11
• Form Factor: Desktop external unit, ribbed black plastic enclosure
• FCC Compliance: Part 15 Class A computing device
• Included: Modem unit only — power adapter NOT included (requires 19VAC 0.80A proprietary 6-pin adapter)

Applications

Microcom's AX/9600 Plus was designed for asynchronous dial-up data communications in the late 1980s and early 1990s, connecting personal computers and terminals to remote hosts, bulletin board systems (BBS), and online services over standard public switched telephone networks (PSTN). MNP Class 6 was Microcom's proprietary protocol suite providing both error correction (MNP Class 4) and data compression (MNP Class 5/6), allowing effective throughput beyond the raw 9600 bps line rate on compatible connections. Microcom developed the MNP standard, which was later incorporated into the ITU V.42 error-correction standard — making Microcom equipment historically significant in the development of modem protocols. These modems were commonly paired with IBM PCs, Apple Macintosh computers, and Unix workstations in office and academic environments during the pre-Internet dial-up era. Today the AX/9600 Plus is sought by vintage computing collectors and hobbyists maintaining period-accurate dial-up setups, BBS systems, and legacy serial communications testbeds.