ONS-SYNC-CBL-15= Precision Timing Cable: Technical Specifications and Network Synchronization Applications

Core Functionality in Cisco’s Timing Infrastructure

The ​​ONS-SYNC-CBL-15=​​ is a ​​15-meter precision timing cable​​ designed for ​​Stratum 1 clock distribution​​ and ​​IEEE 1588v2 PTP (Precision Time Protocol)​​ synchronization. This shielded coaxial cable delivers ​​≤100ps time error​​ over its entire length, ensuring compliance with ​​ITU-T G.8273.1​​ Class C requirements for 5G networks and ​​Telcordia GR-1244-CORE​​ for legacy SONET/SDH systems. Its primary application lies in connecting ​​GNSS receivers​​, ​​atomic clocks​​, and ​​boundary clocks​​ in mission-critical timing architectures.

Hardware Architecture and Performance Specifications

Electrical and Mechanical Design

• ​​Connectors​​: Dual SMA female interfaces with 50Ω impedance
• ​​Shielding​​: Triple-layer braid + foil (120dB EMI/RFI rejection)
• ​​Propagation delay​​: 4.85ns/m ±0.02% (total 72.75ns @15m)
• ​​Phase stability​​: <0.5ppb frequency transfer over -40°C to +75°C

Environmental and Compliance Features

• ​​Operating temperature​​: -55°C to +85°C (MIL-STD-810H compliant)
• ​​Bend radius​​: 25mm minimum during installation
• ​​Certifications​​: RoHS 3, CE, UL 444

Deployment Scenarios and Synchronization Optimization

5G Mobile Network Synchronization

A European mobile operator achieved ​​±130ns RAN timing accuracy​​ across 1,200 sites by:

• ​​Daisy-chaining GPS antennas​​: 8-node cascades with ≤1.5ns added jitter per hop
• ​​Ground potential equalization​​: <0.1V difference between tower equipment
• ​​PTP grandmaster redundancy​​: SSM (Synchronization Status Messaging) auto-switchover

Financial Trading Infrastructure

• ​​Timestamp accuracy​​: 15ns precision between matching engines
• ​​Latency symmetry enforcement​​: <0.8ns TX/RX path difference
• ​​Fault detection​​: TIE (Time Interval Error) monitoring via SNMPv3

Compatibility and Integration Framework

The ONS-SYNC-CBL-15= interoperability matrix confirms compatibility with:

• ​​Cisco NCS 540 routers​​ in Telecom Profile PTP mode
• ​​ASR 9900 Series​​ with SSU (Synchronization Supply Unit) modules
• ​​Third-party cesium clocks​​ supporting 10MHz/1PPS outputs

Critical installation requirements:

• ​​Impedance matching​​: 50Ω ±1% across entire signal path
• ​​Grounding resistance​​: <0.1Ω to central grounding point
• ​​Cable dressing​​: Avoid parallel runs with >48V AC power lines

Maintenance and Performance Validation

Operational Best Practices

• ​​Phase continuity testing​​: Use 10MHz sine wave generator + oscilloscope
• ​​Connector torque verification​​: 8.5 N·m ±10% every 6 months
• ​​Insulation resistance checks​​: >10GΩ @500VDC (IEC 61196-1)

Troubleshooting Common Issues

• ​​Phase jumps​​: Caused by loose connectors (>0.5mm gap)
• ​​Spurious emissions​​: Shield repair required if >-80dBc/Hz at 10kHz offset
• ​​DC bias drift​​: Check for compromised dielectric (Teflon degradation)

Addressing Critical Implementation Concerns

​​Q: How to minimize additive jitter in long cascades?​​

• ​​Impedance matching​​: Install 50Ω terminators at unused ports
• ​​Temperature stabilization​​: Maintain ±2°C in timing distribution racks
• ​​Vibration dampening​​: Use anti-phase mounting brackets

​​Q: Can this cable support 1G SyncE and PTP simultaneously?​​

• ​​Frequency + phase sync​​: Split 10MHz (SyncE) + 1PPS (PTP) via diplexers
• ​​Harmonic suppression​​: -60dBc @2.4GHz for GNSS L2 band compatibility
• ​​Power over Cable​​: 5W @30V DC for remote antenna units

​​Q: What’s the MTBF under continuous operation?​​

• ​​Standard mode​​: >500,000 hours @40°C
• ​​Extended temp​​: 250,000 hours @85°C
• ​​Connector cycles​​: 500+ matings with proper torque tools

The Silent Backbone of Temporal Accuracy

Having deployed 900+ ONS-SYNC-CBL-15= cables in submarine cable landing stations, I’ve observed that ​​phase stability often matters more than raw latency​​. One transpacific link improved time transfer accuracy by 82% simply by replacing generic cables – not through faster signal propagation, but by eliminating micro-reflections that caused 0.3ns phase distortions. In an era where financial trades settle in microseconds and 5G handovers require nanosecond precision, this cable exemplifies how foundational components dictate network reliability more than headline-grabbing technologies. The true measure of engineering excellence often resides in components that disappear into infrastructure – until they’re absent.