Duplex fibre optic patch cords — OS2, OM3, OM4, outdoor

For a switch with SFP+ ports and LR modules (10G single-mode): choose a LC/UPC–LC/UPC OS2 duplex patch cord. This is the standard connector on all SFP+ LR modules. If your switch has SR modules (multimode 850 nm): choose LC/UPC–LC/UPC OM3 or OM4 duplex depending on distance (300 m for OM3, 400 m for OM4). Always check the type of module installed in your switch before ordering.

LC/UPC (blue): flat-polished face, return loss ≥ 50 dB — standard for active equipment (switches, servers, SFP modules). LC/APC (green): 8°-polished face, return loss ≥ 65 dB — required for telecom systems sensitive to reflections (DWDM, optical amplifiers, some OLTs). Warning: LC/UPC and LC/APC are not interchangeable — connecting them together creates additional insertion loss and degrades the link.

No. Single-mode OS2 (9 µm) and multimode OM3/OM4 (50 µm) fibres have incompatible core diameters. A SFP+ SR module (multimode) connected to an OS2 fibre will generate 10 to 20 dB of insertion loss — the link will be non-functional. Always use a patch cord whose fibre type matches the module: OS2 for LR/LX modules (1310/1550 nm), OM3/OM4 for SR modules (850 nm).

By the jacket colour: yellow = OS2 single-mode, aqua/light blue = OM3 multimode, violet/magenta = OM4 multimode, orange = OM1/OM2 (obsolete). The colour of the LC connector also confirms: blue connector = UPC (single-mode or multimode), green connector = APC (single-mode only). These colour codes are defined by TIA-598.

Measure the actual distance between the two devices along the cable path (not in a straight line), then add 10 to 20% as margin for bends and routes. Avoid patch cords that are too long: excess cable coiled in a rack increases bending losses and bulk. Typically: 0.5 to 1 m for switch–server within a rack, 2 to 5 m to link two adjacent racks, 5 to 10 m to link two distant racks or cross a room.

Elfcam patch cords are manufactured to IEC 61755-2-1 (connector characteristics) and IEC 61300-3-35 (ferrule cleanliness) standards. Key parameters are guaranteed: insertion loss ≤ 0.3 dB, return loss ≥ 50 dB (UPC) / ≥ 65 dB (APC), resistance to 500+ mating cycles. Our products are certified CE, RoHS and REACH. For specific carrier certifications (Orange, SFR), please consult our sales team.

A duplex patch cord contains 2 fibres in a jacket and is suitable for point-to-point links at low bitrate or for individual server-switch connections in a datacenter. An MPO trunk cable (12, 24 or 48 fibres) in a single connector is used for high-density links in datacenters: one MPO-12 cable is equivalent to 6 simultaneous duplex patch cords and supports aggregate bitrates of 40, 100 or 400 Gbit/s. See Elfcam MPO cables →.

All Elfcam duplex patch cords (LC/UPC OS2, LC/APC OS2, SC/APC OS2, OM3, OM4, armoured outdoor) are available in stock in France with shipping within 24 working hours. Orders placed before 2:00 pm are shipped the same day. For structured cabling projects in large quantities, tiered pricing and guaranteed delivery times are available on request via our contact form.