CCS Micro 56+ 601556 V.35 Audio HF Boost Rackmount DSU/CSU 85-265VAC 50/60Hz

CCS Micro 56+ 601556 V.35 Audio HF Boost Rackmount DSU/CSU 85-265VAC 50/60Hz

The Corporate Computer Systems CCS Micro 56+ is a 1U rackmount DSU/CSU (Data Service Unit/Channel Service Unit) designed for V.35 WAN interface applications. Model number 601556, manufactured by Corporate Computer Systems, Inc. of Holmdel, NJ, the Micro 56+ distinguishes itself with a built-in audio high-frequency boost circuit and XLR balanced audio connections — features oriented toward integrated voice and data applications over leased or switched 56 Kbps digital circuits.

Specifications & What's Included

• Manufacturer: Corporate Computer Systems, Inc. (Holmdel, NJ)
• Model: CCS Micro 56+ (CCS MICRO 56+)
• Part / Model Number: 601556
• Internal Product Code: CCS0895
• Form Factor: 1U Rackmount
• Power Input: 85-265VAC, 50/60Hz (universal wide-range input)
• Power Entry: IEC C14 inlet with rear panel rocker power switch
• WAN Interface: V.35 (34-pin Winchester connector on rear panel)
• Audio Input: XLR balanced connector (rear panel)
• Audio Output: XLR balanced connector (rear panel)
• Alarm Port: 3.5mm connector (rear panel)
• Front Panel Controls: Audio HF Boost switch (On/Off), Loopback switch (LB/Normal)
• Front Panel Indicators: Input/Overload LED, Receiver Framed LED, Power LED
• Chassis: Black anodized steel, rack ears integrated
• Unit only — no cables included

Applications

DSU/CSU units like the CCS Micro 56+ served as the customer-premises termination equipment for leased 56 Kbps and fractional T1 digital data circuits in the 1980s and 1990s. The DSU converts the DTE (data terminal equipment) signal — here via V.35 — into the bipolar line format required by the telco's digital local loop, while the CSU portion terminates the line, provides loopback testing capability, and maintains line conditioning. The CCS Micro 56+ was aimed at applications where analog audio needed to ride alongside or integrate with the digital data path, reflected by its built-in audio HF boost circuit and balanced XLR audio connections — a configuration found in broadcast, telecom, and corporate AV-over-WAN installations of that era. The front-panel loopback switch allows in-service loop testing without additional test equipment, a standard diagnostic feature for circuit troubleshooting. While switched 56 and analog leased-line circuits have been largely superseded by broadband and IP-based WAN technologies, units like this remain relevant for legacy private-line circuit maintenance, museum/broadcast archive infrastructure, and specialized telecommunications environments that have not migrated away from V.35 serial interfaces.