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3. Key Technical Specifications
| Parameter | Value / Description |
|---|---|
| Model | LMC009A-R5 |
| Manufacturer | Black Box |
| Conversion Type | Twisted Pair (10Base-T) ↔ 50-ohm Coax (10Base-2) |
| Data Rate | 10 Mbps |
| Connectors | 1 × RJ-45 (shielded) + 1 × BNC |
| Power Supply | Internal 100–240 VAC, 50/60 Hz |
| Form Factor | Compact standalone / approx. 1U high |
| Operating Temperature | 0°C to +50°C (+32°F to +122°F) |
| Storage Temperature | –20°C to +70°C |
| Humidity | 5–90% non-condensing |
| Indicators | Front-panel diagnostic LEDs |
| Typical Use | Legacy coax network extension / migration |
4. Product Introduction
The Black Box LMC009A-R5 is a compact media converter that bridges 10Base-T twisted-pair Ethernet and 10Base-2 50-ohm coaxial (thin coax) networks. It allows existing 50-ohm coax cabling (such as RG-59) to remain in service while connecting to modern twisted-pair switches or devices.
The unit features an internal universal AC power supply, eliminating the need for an external power adapter, and provides front-panel LEDs for quick status checks. It is commonly used in industrial plants, older manufacturing facilities, and military or specialized systems that still rely on coaxial Ethernet segments.
LMC009A-R5
LMC009A-R5
5. Troubleshooting Quick Reference
| Symptom | Possible Cause | Relevance to this Part | Quick Check Method | Recommendation |
|---|---|---|---|---|
| No link on either side | Power or cable fault | ✅ High | Verify power LED and cable continuity | Restore power; test cables |
| Link on TP but not on coax | Coax termination or cable issue | ✅ High | Check BNC terminators and coax integrity | Install proper 50-ohm terminators; replace cable |
| Link on coax but not on TP | Twisted-pair cable or port fault | ✅ High | Test RJ-45 cable and far-end device | Replace TP cable or try different port |
| Intermittent connectivity | Poor coax grounding or length | ✅ Medium | Verify coax length (<185 m) and grounding | Shorten run or improve grounding |
| No power LED | AC supply or internal PSU failure | ✅ High | Measure AC input voltage | Confirm mains power; replace unit if PSU failed |
| High error rate | Impedance mismatch or noise | ✅ Medium | Confirm 50-ohm coax and proper terminations | Use correct cable type and terminators |
Always power down before connecting or disconnecting cables. Use only 50-ohm coaxial cable and proper terminators on the BNC side.
6. Frequently Asked Questions (FAQ)
Q: What does the LMC009A-R5 convert?
It converts between 10Base-T twisted-pair Ethernet (RJ-45) and 10Base-2 50-ohm thin coaxial Ethernet (BNC).
Q: Does it support 100 Mbps or Gigabit?
No. It is a 10 Mbps converter only.
Q: Does it need an external power supply?
No. It has a built-in internal 100–240 VAC power supply.
Q: What coax cable should I use?
50-ohm coaxial cable (commonly RG-59 or equivalent). Do not use 75-ohm video coax.
Q: Is this model still available?
The LMC009A-R5 is a legacy product. New-old-stock and surplus units remain available for maintenance of existing coax-based networks.
Q: What should I check before replacement?
Confirm you need 10Base-T to 50-ohm BNC conversion, verify AC power availability, and photograph the existing unit’s labels and connections.
Install with correct 50-ohm terminators on the coax segment, use quality twisted-pair cabling on the RJ-45 side, and verify link LEDs on both ports after power-up. This restores connectivity between legacy coax and modern twisted-pair networks.
