US Robotics USR5633A 56K Fax Modem USB External Dial-Up V.90 Phone Telco

US Robotics USR5633A 56K Fax Modem USB External Dial-Up V.90 Phone Telco

The US Robotics USR5633A is an external 56K dial-up fax modem that connects to a PC via USB and draws all its power from the USB bus — no external power adapter needed. It supports the V.90 standard at up to 56 Kbps and includes both a Phone and a Telco RJ-11 port for direct connection to a standard telephone line while keeping a handset connected. Indicator LEDs on the top face show connection status at a glance.

Specifications & What's Included

• Brand: US Robotics
• Model / Part Number: USR5633A (Model 5633)
• Maximum Data Rate: 56 Kbps (V.90)
• Fax Capability: Yes
• Interface: USB (USB-B connector)
• Power Source: USB bus-powered — no AC adapter required
• Phone Line Connectors: RJ-11 PHONE port + RJ-11 TELCO port
• Form Factor: External desktop
• Certifications: FCC (ID: CJEM609B5633), UL Listed ITE, CE 0682
• Country of Manufacture: China
• Includes: Modem unit only — no USB cable included

Applications

The USR5633A belongs to the final generation of external dial-up modems, produced in the early-to-mid 2000s when broadband was displacing POTS dial-up as the dominant consumer internet technology. USB-powered external modems like this one were a popular choice for laptop users and desktop PCs that lacked an internal modem slot, or as a simple plug-and-play replacement. The V.90 standard, introduced in 1998, unified competing 56K protocols (X2 and K56flex) and became the last major ITU analog modem standard before dial-up fell out of mainstream use. Today, dial-up modems still see niche use in legacy industrial control systems, point-of-sale terminals, fax-over-POTS applications, and remote telemetry systems that rely on PSTN lines where broadband is unavailable. The Phone/Telco dual-port design allows a telephone handset to share the same line without unplugging the modem.