IBM 5822-018 56K DSU/CSU RS-232 V.35 Rackmount T1 FT1 Module 1989

IBM 5822-018 56K DSU/CSU RS-232 V.35 Rackmount T1 FT1 Module 1989

The IBM 5822-018 is a 56K DSU/CSU (Data Service Unit/Channel Service Unit) designed for T1 and Fractional T1 (FT1) WAN connections. It provides the interface between customer premises data terminal equipment (DTE) and the digital telephone network, supporting both RS-232 and V.35 DTE interfaces. Manufactured by IBM in 1989, this is a rackmount card/module form factor that installs into a compatible IBM shelf or chassis.

Specifications & What's Included

• Brand: IBM
• Model / Type: 5822-018
• Function: DSU/CSU — Data Service Unit / Channel Service Unit
• Data Rate: 56 Kbps (FT1) / up to 1.544 Mbps (T1)
• DTE Interface: RS-232, V.35
• Form Factor: Rackmount card/module (card-edge bus connectors on bottom)
• Front Panel LEDs: TST (Test), AL (Alarm), LNK (Link), ACT (Activity), RD (Receive Data), TD (Transmit Data)
• Front Panel Connector: Single port with latch housing (broken plastic on latch — see photos)
• Year of Manufacture: 1989 (IBM Corp. label visible)
• Quantity: Two (2) units available; both have the same broken plastic condition on the face cover latch

Applications

DSU/CSU units like the IBM 5822-018 were the standard interface between a business's data network equipment and leased T1 or Fractional T1 lines provided by a telephone carrier. The DSU converts the DTE's digital data signals (RS-232 or V.35) into the bipolar line format required by the T1 network, while the CSU provides line termination, signal conditioning, and loopback testing capability required by the carrier. IBM's 5822 series was used in corporate data centers and branch offices during the late 1980s and 1990s as part of IBM's SNA (Systems Network Architecture) and WAN infrastructure, connecting mainframes, AS/400 systems, and IBM-compatible routers to wide-area leased lines. The card-edge rackmount form factor indicates it was designed for installation in a specific IBM shelf or wiring concentrator chassis common to that era. While T1 DSU/CSU technology has largely been superseded in new deployments by integrated WAN routers, these units are still sought for legacy IBM network maintenance and for environments where existing T1 circuits and IBM WAN infrastructure remain in service.