The **LMC100A-RJ-R2** is a high-performance **Fast Ethernet Media Converter** manufactured by Black Box. Its primary electronic function is to bridge the gap between different physical transmission media—specifically converting **10/100Base-TX (Copper)** signals to **100Base-FX (Fiber)**. --- ### 1. Key Technical Specifications The following table outlines the core electronic and physical attributes of the device: | Feature | Specification | | :--- | :--- | | **Data Rate** | 10/100 Mbps (Auto-negotiating) | | **Copper Interface** | RJ-45 (Shielded) | | **Fiber Interface** | Multi-mode (MM) with SC Connectors | | **Fiber Wavelength** | 1310 nm | | **Maximum Distance** | Up to 2 km (1.2 miles) over Multi-mode fiber | | **Input Power** | 5 VDC, 1A (via external power adapter) | | **Operating Temp** | 0°C to 50°C (32°F to 122°F) | --- ### 2. Internal Electronic Architecture The LMC100A-RJ-R2 utilizes several key electronic systems to ensure data integrity during conversion: #### A. Transceiver Module The unit contains an integrated optical transceiver. It converts electrical pulses from the copper wire into light pulses for the fiber optic cable using a **1310nm LED or Laser diode**, and converts incoming light back into electrical signals using a **Photodetector**. #### B. Link Loss Carry Forward (LLCF) & Link Fault Pass-Through (LFP) These are critical diagnostic circuits. If a link fails on the fiber side, the electronics "force" the copper side to drop as well. This ensures that the connected switches or routers are aware of the link failure and can route traffic through a backup path. #### C. Auto MDI/MDI-X The copper port electronics include an automatic crossover detection circuit. This eliminates the need for "crossover cables" when connecting to different types of Ethernet hardware. --- ### 3. Connection Overview The device serves as a physical layer converter. Below is the typical pinout logic for the RJ-45 side: ```text RJ-45 Pinout (Standard T568B): 1: Tx+ (Transmit Data +) 2: Tx- (Transmit Data -) 3: Rx+ (Receive Data +) 6: Rx- (Receive Data -) ``` ### 4. LEDs and Diagnostics The front panel includes several Status Indicator LEDs driven by the internal logic board: * **PWR:** Indicates the internal DC-DC converter is providing stable voltage. * **LNK/ACT:** Shows the physical integrity of the fiber and copper connections. * **100:** Indicates the port is operating at 100 Mbps speed. ---