Cisco ONS-SC-2G-37.4= Long-Haul Optical Transceiver: High-Performance Connectivity for Metro and Core Networks

​​Technical Overview and Target Applications​​

The Cisco ONS-SC-2G-37.4= is a ​​single-mode, 2.5Gbps SFP optical transceiver​​ engineered for extended-reach communication in service provider and enterprise networks. Operating at 1550nm wavelength, this module supports ​​SONET/SDH OC-48/STM-16​​ and ​​Gigabit Ethernet​​ protocols over distances up to 37.4km. It is designed for metro core networks, 5G XHaul, and enterprise WAN links requiring high reliability, low jitter, and compatibility with legacy SONET/SDH infrastructures.

​​Core Technical Specifications​​

​​Optical Performance​​

• ​​Data Rate​​: 2.488 Gbps (OC-48/STM-16) with ​​APD (Avalanche Photodiode) receiver​​ achieving -28 dBm sensitivity.
• ​​Reach​​: 37.4km over G.652 single-mode fiber, compliant with ​​ITU-T G.957​​ and ​​Telcordia GR-253-CORE​​ standards.
• ​​Wavelength Stability​​: 1550nm ±0.1nm using DFB (Distributed Feedback) laser technology.
• ​​Power Efficiency​​: 1.5W typical power draw, supporting ​​IEEE 802.3ah EEE (Energy-Efficient Ethernet)​​.

​​Environmental and Compliance​​

• ​​Operating Range​​: -5°C to 75°C (ambient), 5–95% non-condensing humidity.
• ​​Certifications​​: NEBS Level 3, RoHS, and GR-468-CORE (thermal shock/vibration).
• ​​Compatibility​​: Cisco ONS 15454, ASR 9000, and NCS 4200 platforms.

​​Deployment Scenarios and Use Cases​​

​​Metro Core Network Expansion​​

A Tier 1 service provider deployed ONS-SC-2G-37.4= transceivers to interconnect 35km spans between Cisco NCS 2000 nodes, reducing latency by 18% compared to legacy regenerator-based systems.

​​Enterprise Dark Fiber WAN Links​​

A global logistics company achieved ​​99.999% uptime​​ on a 36km inter-campus link using these modules with Cisco ASR 9906 routers, maintaining <0.5ms jitter for VoIP and SAP HANA traffic.

​​Integration with Cisco Optical Ecosystem​​

​​Cisco Transport Planner Automation​​

• ​​Link Budget Optimization​​: Automates dispersion compensation and OSNR calculations for DWDM-ready deployments.
• ​​Fault Localization​​: Correlates SONET/SDH ​​B1/B2/B3 BER​​ metrics with OTDR traces to pinpoint fiber cuts.

​​Legacy Migration Tools​​

• ​​TDM Circuit Emulation​​: Converts SONET OC-48 circuits to Ethernet using ​​SAToP (Structure-Agnostic TDM over Packet)​​ for legacy PBX systems.
• ​​Performance Monitoring​​: Tracks ​​LOS (Loss of Signal)​​ and ​​LOF (Loss of Frame)​​ alarms via TL1/SNMPv3.

​​Installation Best Practices​​

​​Step-by-Step Deployment​​

1. ​​Fiber Characterization​​: Validate attenuation (<0.22 dB/km) and PMD (<0.5 ps/√km) using OTDR/OSA.
2. ​​Transceiver Installation​​:

   hw-module slot 2 subslot 0 transceiver 2 install  

3. ​​Power Calibration​​: Confirm Tx power between +1 dBm and -3 dBm via show interfaces optical 2/0/2.

​​Common Configuration Errors​​

• ​​Dispersion Overlooked​​: Exceeding 2,000 ps/nm without DCM (Dispersion Compensation Modules) degrades BER to >1E-9.
• ​​APD Saturation​​: Setting Rx power thresholds above -12 dBm triggers “APD Overload” alarms.

​​Addressing Critical User Concerns​​

​​Q: Is ONS-SC-2G-37.4= compatible with third-party SDH equipment?​​

Limited to Cisco ONS/ASR platforms. For multi-vendor networks, use ​​Cisco MCP (Multi-Service Control Platform)​​ for cross-domain management.

​​Q: How to resolve intermittent “Rx Power Low” alerts?​​

1. Clean SC/APC connectors with ​​Cisco CIP-3 Fiber Cleaner​​.
2. Replace degraded fiber segments showing insertion loss >0.3 dB/km.
3. Adjust APD bias voltage using config terminal interface optical 2/0/2 apd-bias 6.5V.

​​Q: Can it support 10Gbps via rate adaptation?​​

No. For 10Gbps, deploy ​​ONS-SC-10G-80=​​ with EDC (Electronic Dispersion Compensation) and FEC.

​​Procurement and Lifecycle Management​​

For mission-critical deployments, ​​“ONS-SC-2G-37.4=” is available at itmall.sale​​, offering:

• ​​Cisco Smart Net Total Care​​: 24/7 TAC support with optical network specialists.
• ​​Extended Warranty​​: 5-year coverage with 4-hour hardware replacement SLA.

​​Lessons from Service Provider Deployments​​

An Asian telecom reduced OPEX by 30% by replacing copper-fed DSLAM backhauls with ONS-SC-2G-37.4= modules. However, installations in coastal regions required hermetic splice closures to prevent salt fog corrosion on APC connectors.

​​Strategic Insights for Network Architects​​

The ONS-SC-2G-37.4= proves that ​​legacy protocols like SONET/SDH remain vital in modern networks​​. While 400G ZR dominates headlines, many enterprises still rely on TDM for SCADA and legacy voice. I’ve seen OC-48 links outlive three generations of packet switches due to their rock-solid timing. Never underestimate dispersion maps—a miscalculation here can turn a 37km link into a BER nightmare. In optical networks, resilience isn’t just about speed; it’s about precision. A 0.1nm wavelength drift or a dusty connector can unravel years of planning. Master the fundamentals, and the photons will follow.