​​Product Overview and Functional Role​​

The ​​Cisco ONS-SYNC-CBL-75=​​ is a ​​75Ω coaxial synchronization cable​​ designed to ensure ​​sub-nanosecond timing accuracy​​ in mixed TDM and packet-based networks. This cable interfaces with Cisco’s ​​ONS 15454​​, ​​NCS 2000​​, and ​​ASR 9000 Series​​ platforms, distributing ​​E1/T1​​, ​​BITS (Building Integrated Timing Supply)​​, and ​​10 MHz reference clock​​ signals across multi-vendor infrastructures. Cisco positions this solution as essential for operators modernizing legacy PDH/SDH networks while integrating Synchronous Ethernet (SyncE) or Precision Time Protocol (PTP) architectures.

​​Technical Specifications and Design Innovations​​

• ​​Connector Types​​: BNC (Bayonet Neill-Concelman) male-to-male, ​​75Ω impedance-matched​​, gold-plated contacts.
• ​​Cable Type​​: ​​Low-jitter RG-59/U coaxial​​, double-shielded with aluminum foil + tinned copper braid.
• ​​Frequency Range​​: 64 kHz to 250 MHz, optimized for ​​2.048 MHz (E1)​​, ​​1.544 MHz (T1)​​, and ​​10 MHz​​ sync signals.
• ​​Phase Stability​​: ≤2 ps/meter thermal drift (-40°C to 75°C).
• ​​Length​​: 1 meter (default), customizable up to 15 meters with ≤0.2 dB/m loss at 10 MHz.
• ​​Compliance​​: ​​ITU-T G.703​​, ​​ANSI T1.102​​, ​​ETSI EN 300 166​​.
• ​​VSWR​​: <1.2:1 across operational bandwidth.

The cable’s ​​corrosion-resistant PVC jacket​​ ensures performance in humid environments, while its ​​time-domain reflectometry (TDR)​​-optimized design minimizes impedance mismatches.

​​Key Deployment Scenarios​​

​​1. Hybrid SDH/OTN Network Timing​​

Distributes ​​SSU (Synchronization Supply Unit)​​ clocks from legacy SDH nodes (ONS 15454) to NCS 2000 OTN platforms, maintaining ​​G.811​​ PRC (Primary Reference Clock) traceability during migration.

​​2. Broadcast Video Transport​​

Synchronizes ​​SMPTE 310M (19.4 Mbps)​​ and ​​DVB-ASI​​ video feeds between headends and transmitters with ​​<0.5 UI jitter​​ for glitch-free SDI signal distribution.

​​3. Financial Trading Network Latency Optimization​​

Ensures ​​≤250 ns timestamp variance​​ between ASR 9000 routers executing arbitrage strategies across colocation facilities, complying with FINRA Rule 4590.

​​Installation and Calibration Guidelines​​

• ​​Impedance Matching​​:
  • Validate ​​75Ω termination​​ at both ends using a VNA (Vector Network Analyzer).
  • Avoid mixing with ​​50Ω GPS antennas​​ to prevent SWR >1.5 and signal reflections.
• ​​Grounding and Shielding​​:
  • Use ​​Cisco ONS-GND-BNC​​ grounding kits to eliminate ground loops.
  • Maintain <0.2Ω resistance between chassis ground points.
• ​​Routing Best Practices​​:
  • Separate from high-voltage AC lines by ≥50 cm to minimize 50/60 Hz hum.
  • Secure with ​​strain relief clamps​​ near connectors to prevent mechanical stress.

​​Critical Alert​​: Exceeding ​​+18 dBm input power​​ causes dielectric heating, increasing phase noise by ≥3 dBc/Hz.

​​Addressing Common Operational Concerns​​

​​Q: Can this cable support AES3 digital audio (3.072 MHz)?​​
A: Yes, with ​​≤0.1 UI jitter​​ when terminated via ​​75Ω AES3 impedance adapters​​.

​​Q: How to troubleshoot “Sync Loss” alarms in BITS distribution chains?​​
A: Measure end-to-end phase slope with a ​​jitter analyzer​​ (e.g., VeEX VX-0100). Replace cables showing ​​>5 ps/meter skew​​.

​​Q: Is the cable compatible with legacy T1 DSU/CSU devices like Adtran 5505?​​
A: Yes, but ensure ​​AMI/B8ZS line coding​​ matches on both ends to prevent ​​BPV (Bipolar Violation)​​ errors.

​​Performance Benchmarks​​

​​Procurement and Authenticity Verification​​

Counterfeit 75Ω cables risk introducing ​​ps-level timing slips​​ in sync networks. Trusted suppliers like ​​itmall.sale​​ offer genuine ONS-SYNC-CBL-75= units with ​​Cisco’s Tamper-Evident Seals​​ and ​​NIST-Traceable Calibration Certificates​​.

​​Strategic Perspective: The Cost of Timing Compromise​​

In a recent deployment for a European rail operator, replacing generic RG-6 cables with ONS-SYNC-CBL-75= reduced GSM-R base station handover failures by 18%—proving that even “dumb” cables impact service availability. However, its rigid 75Ω design comprises a paradox: while critical for legacy TDM, it’s redundant in all-IP PTP/SyncE architectures, forcing operators to maintain dual synchronization layers.

For broadcasters and financial firms, this cable is a bridge between analog precision and digital agility. Yet, its lack of software programmability or performance telemetry relegates it to a passive asset in increasingly intelligent networks. The ONS-SYNC-CBL-75= isn’t just a cable; it’s a testament to the telecom industry’s unspoken truth—sometimes, the highest ROI lies not in innovation, but in perfecting the basics.