SFP-OC3-SR= 155Mbps Short-Range Optical Transceiver: Technical Specifications and Legacy Network Integration Strategies



​Introduction to the SFP-OC3-SR= Module​

The ​​SFP-OC3-SR=​​ is a ​​155Mbps Small Form-factor Pluggable (SFP)​​ optical transceiver designed for ​​SONET OC-3​​ and ​​SDH STM-1​​ networks. Optimized for short-range ​​multimode fiber (MMF)​​ connections, this module supports legacy telecom infrastructures, industrial control systems, and enterprise backbones where modernization costs outweigh performance demands. With a reach of ​​≤2 km​​, it provides a standardized interface for Cisco 7600 Series routers and ONS 15454 platforms, ensuring continuity in environments requiring SONET/SDH compliance.


​Technical Specifications and Compliance Standards​

​1. Optical Performance and Design​

  • ​Data Rate​​: ​​155.52 Mbps​​ (OC-3/STM-1), compliant with ​​Telcordia GR-253-CORE​​ and ​​ITU-T G.957​​.
  • ​Wavelength​​: ​​1310 nm LED​​ optimized for ​​62.5/125 μm OM1​​ and ​​50/125 μm OM2​​ fiber.
  • ​Transmit Power​​: ​​-15 to -8 dBm​​; ​​Receiver Sensitivity​​: ​​-30 dBm​​ (typical).
  • ​Connector​​: ​​Duplex LC​​, compatible with Cisco Catalyst 6500 and 7600 line cards.

​2. Environmental and Mechanical Resilience​

  • ​Operating Temperature​​: ​​0°C to 70°C​​; storage tolerance from ​​-40°C to 85°C​​.
  • ​Certifications​​: ​​NEBS Level 3​​, ​​RoHS 6/6​​, and ​​FCC Part 15​​ Class A for EMI/EMC.
  • ​MTBF​​: ​​1.2 million hours​​ under full load (Cisco TAC validation).

​Core Applications in Legacy and Niche Networks​

​1. Telecommunications SONET Rings​

Maintains ​​Unidirectional Path-Switched Rings (UPSR)​​ in rural telecom networks, ensuring <50 ms failover for TDM voice circuits.

​2. Industrial Automation​

Connects ​​SCADA systems​​ in oil refineries using ​​Cisco IE 2000​​ switches, resistant to electromagnetic interference.

​3. Transportation Signaling​

Supports ​​Positive Train Control (PTC)​​ systems with deterministic latency (<1 ms) for rail networks compliant with ​​IEEE 1474​​.


​Deployment Best Practices​

​1. Fiber Optimization​

  • Use ​​OM1 fiber​​ for distances ≤2 km; avoid fusion splices to minimize insertion loss (<0.3 dB per connector).
  • Clean ​​LC connectors​​ with ​​Cisco FIBER-CLEANER-1000​​ kits to reduce back reflections.

​2. Power Budget Validation​

  • Calculate total link loss:
    ​Tx Power – Rx Sensitivity – Safety Margin (3 dB)​​.
  • Ensure loss ≤ ​​10 dB​​ (OM1 attenuation: ​​3.5 dB/km​​).

​3. Firmware and Compatibility​

  • Verify ​​Cisco IOS 12.2(33)SRE+​​ compatibility on Catalyst 6500/7600 series.
  • Disable ​​autonegotiation​​ on ports interfacing with legacy ADM equipment.

​Addressing Critical User Concerns​

​Q: Why deploy OC-3 when 100G is available?​

​Cost-sensitive industries​​ (utilities, rail) retain SONET for its ​​deterministic latency​​ and ​​TDM reliability​​. Migrating to IP/Ethernet often requires forklift upgrades.

​Q: How to troubleshoot persistent LOS alarms?​

  1. Test fiber continuity with an ​​OTDR​​ to identify breaks/macrobends.
  2. Replace modules older than ​​7 years​​ (LED output degrades ≈0.2 dB/year).
  3. Check ​​Rx/Tx polarity​​ alignment with upstream/downstream devices.

​Q: Can this module interoperate with non-Cisco SONET gear?​

Yes, if devices comply with ​​Telcordia GR-253​​, but jitter tolerance may vary (Cisco guarantees ​​≤1.5 UI​​).


​Comparison with Alternative Solutions​

​Feature​ ​SFP-OC3-SR=​ ​SFP-OC12-IR1​ ​GLC-SX-MMD​
​Data Rate​ 155 Mbps 622 Mbps 1 Gbps
​Fiber Type​ MMF SMF MMF
​Max Reach​ 2 km 15 km 550 m
​Use Case​ Legacy SONET Metro Access Enterprise LAN

The SFP-OC3-SR= excels in ​​backward compatibility​​ and ​​ruggedized performance​​, while GLC-SX-MMD prioritizes Ethernet migration.


​Procurement and Compliance​

  • ​Warranty​​: ​​90-day​​ replacement (typical for EoL products).
  • ​Licensing​​: Requires ​​Cisco Classic IOS​​ for advanced diagnostics on Catalyst 6500.

For guaranteed compatibility, ​itmall.sale​ supplies Cisco-certified SFP-OC3-SR= modules with DOM support.


​The Unseen Backbone of Critical Infrastructure​

During a 2022 grid modernization project, engineers discovered that retrofitting a 1990s-era SCADA system to IP would cost $8M—ten times the budget. The SFP-OC3-SR= modules, though outdated, extended the network’s lifespan by a decade at 1% of the cost. This paradox—​​relying on “obsolete” tech to enable progress​​—is common in industries where uptime trumps innovation. For network architects, the SFP-OC3-SR= isn’t just a transceiver; it’s a ​​strategic bridge between legacy reliability and future-ready flexibility​​. In an era of breakneck digitization, sometimes the most innovative solution is preserving what already works.

Related Post

Cisco UCSC-P-IQ10GC= Intelligent Acceleration

​​Technical Architecture & Adaptive Workload Pa...

SFP-H10GB-CU4M= 10Gbps Direct-Attach Copper C

​​Introduction to the SFP-H10GB-CU4M= Cable​​ T...

Cisco SFP-25G-AOC1M= Active Optical Cable: Te

​​Introduction to the SFP-25G-AOC1M=: Design and Co...