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1. PRODUCT OVERVIEW
The AT‑MC104LH is a professional‑grade Fast Ethernet media converter manufactured by Allied Telesyn. It belongs to the AT‑MC10x series of fiber‑to‑copper media conversion devices and is identified by article number and model designation AT‑MC104LH. This model is designed specifically to convert between single‑mode long‑haul (LH) fiber using SC connectors and multimode fiber using SC connectors, enabling long‑distance network expansion up to 40 km. The product serves as a compact standalone device but can also be integrated into 19‑inch rack chassis systems for multi‑converter deployments. It is engineered for use in enterprise, industrial, and large‑scale network environments requiring flexible fiber‑optic interconnection and Twisted Pair network extension.

2. KEY FEATURES
The AT‑MC104LH incorporates key features supporting robust network operation, high reliability, and flexible deployment. These include:
• Single‑mode long‑haul SC fiber to multimode SC fiber conversion up to 40 km distance
• Support for multi‑ and singlemode fiber optical interfaces in common wavelength ranges (100FX, 100SX, 100BaseFX, Longhaul)
• Integrated auto‑negotiation on Fast Ethernet links for full‑duplex or half‑duplex bandwidth optimization
• “Missing Link” functionality reporting fiber‑link failures to network switches, enabling redundancy mechanisms
• Internal MDI/MDIX switching for automatic Twisted Pair port crossover selection
• Built‑in link test mode for fiber‑path integrity diagnostics without external instruments
• Operation as standalone device or rack‑mountable via 19‑inch chassis with optional redundant power
• Continuous operation reliability ensured through unlimited lifetime functional warranty and free technical support
• Full compliance with international safety, EMC, and optical standards
These features make the AT‑MC104LH a versatile solution for extending network reach across fiber infrastructures while maintaining compatibility with standard Fast Ethernet equipment.

3. TECHNICAL SPECIFICATIONS
Dimensions: 105 × 95 × 25 mm
Weight: 294 g
Operating temperature: 0° to 50°C
Storage temperature: –20° to 80°C
Relative humidity: 5% to 80%, non‑condensing
Housing style: Compact standalone converter, metal enclosure
Power input: 12 VDC ±5%
Power consumption: 6 W maximum
Current requirement: 0.5 A
Mechanical/EMC certifications: FCC Class A, IC Class A, UL, CSA, TÜV, IEC 825‑1, CE compliant

Fiber‑optic interface capabilities include multiple wavelength ranges and sensitivity levels. For multimode 100FX operation, optical wavelength is typically 1300 nm with sensitivity at –34.5 dBm and maximum optical output power –14 dBm. For 100SX multimode operation, wavelength range is 810–850 nm with typical sensitivity –30 dBm and maximum output –12 dBm. Additional multimode transmitter power values vary by cable type (62.5/125 µm at –16.8 dBm; 50/125 µm at –20.3 dBm). For 100BaseFX long‑haul single‑mode operation, typical wavelength is 1300 nm with output between –15 and –8 dBm and sensitivity around –31 dBm.

For single‑mode long‑haul operation, the optical wavelength range is 1280–1335 nm for transmission and 1260–1360 nm for reception. Sensitivity is typically –38 dBm with a maximum of –35 dBm. Optical output power for LH single‑mode is typically –3 dBm with a range of –5 to –0 dBm.

Twisted‑pair electrical specifications include differential output voltage between 950 and 1050 mV (typical 980 mV), overshoot less than 5%, amplitude symmetry range 0.98–1.02, rise time between 3.0 and 5.0 ns (typical 4.6 ns) and fall time between 3.0 and 5.0 ns (typical 4.2 ns). Rise/fall time symmetry is typically 0.4 ns with a maximum of 0.5 ns.

4. FUNCTIONALITY
The AT‑MC104LH functions as an optical media converter linking networks based on different fiber types. It converts between long‑haul single‑mode SC fiber signals and multimode SC fiber signals, enabling flexible network bridging where fiber types or distances vary. Through its Twisted Pair capability, it can also operate in networks extending copper infrastructure over fiber.

Core operational behaviors include:
• Auto‑negotiation: When connected to Fast Ethernet auto‑negotiation switches, the converter selects optimal full‑duplex or half‑duplex communication parameters.
• Missing Link: A mechanism reporting fiber failures to connected switches; if a fiber path fails, redundancy systems can activate alternative links.
• Link test mode: Allows verification of fiber link integrity by enabling bidirectional communication between paired converters. This identifies cable faults without requiring external optical test equipment.
• MDI/MDIX: Automatic configuration of crossover or straight‑through TP wiring.
• Compatible with standard Fast Ethernet (100 Mbps) copper and fiber networking equipment.
Use cases include campus networks, industrial buildings, metropolitan connections, and fiber backbone extensions.

5. COMPONENTS & ACCESSORIES
Included with the AT‑MC104LH:
• Standalone media converter unit
• External 12 VDC power supply
• SC optical interfaces for both single‑mode LH and multimode fiber
• Twisted Pair port with automatic MDI/MDIX
Optional accessories:
• 19‑inch rack‑mount chassis supporting up to 12 converters
• Optional second internal chassis power supply for redundancy
• Fiber patch cables (SC–SC multimode or single‑mode)
• Management system integration via switch‑level diagnostics (Missing Link)

6. INSTALLATION & SETUP
The AT‑MC104LH is designed for simple, rapid deployment.
Installation steps include:
• Connect multimode SC fiber to the MM optical port
• Connect single‑mode long‑haul SC fiber to the LH SM fiber port
• Connect TP interface to a PC, hub, or switch using a standard RJ‑45 cable (MDI/MDIX auto‑sensing eliminates crossover cables)
• Apply power using the supplied external 12 VDC adapter
• Configure Normal/Test switch to Normal for standard operation or Test for fiber‑link diagnostics
Mounting options include standalone desk placement or integration into the 19‑inch chassis supporting multiple converters. When used with the chassis, power is supplied centrally, and dual power modules may be installed for load sharing and redundancy.

7. PERFORMANCE & CAPABILITIES
Maximum cable distances:
• Twisted Pair Category 5: 100 m
• Multimode FX: 2000 m (full‑duplex), 412 m (half‑duplex)
• Single‑mode FX: 15 km (full‑duplex), 412 m (half‑duplex)
• Single‑mode long‑haul (LH): 40 km (full‑duplex), 412 m (half‑duplex)

Performance parameters:
• Bit error rate (BER) better than 10⁻⁹
• Round trip delay up to 0.4 s
• Optical power ranges support long‑distance, low‑loss communications
• Efficient 6 W power draw minimizes thermal load
• Operational reliability across 0–50°C environments

The unit supports high‑integrity Fast Ethernet with consistent throughput and robust error‑handling mechanisms.

8. STANDARDS & COMPLIANCE
The AT‑MC104LH complies with major international electrical, mechanical, and optical standards:
• FCC Class A
• IC Class A
• UL, CSA, TÜV certified
• IEC 825‑1 (laser safety)
• CE compliant for European operation
These certifications ensure suitability in enterprise, industrial, and controlled environments with strict electromagnetic and safety requirements.

9. ADDITIONAL INFORMATION
Warranty: Allied Telesyn provides an unlimited lifetime functional warranty and free technical support for all Fast Ethernet media converters, ensuring long‑term operational security.
Maintenance: Includes simple visual diagnostics via front‑panel LEDs (Power, Link, Receive, Normal/Test). Regular cleaning of fiber connectors is recommended for optimal optical performance.
Support: Available through Allied Telesyn EU offices in the UK, Germany (Berlin and Freising), Austria, France, Italy, and Spain.
Product code: 617‑00275‑05
Manufacturer website: www.alliedtelesyn.com
Software/firmware: Not required for operation; device is hardware‑based.

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