An SC to SC patch cord is a fibre cable with a square, push-pull SC connector on a 2.5 mm ferrule at each end. It is the usual cord in FTTH and PON frames, splitters and ONTs (SC/APC, green), telecom exchanges and media converters. Each end's polish must match its port. Radix Fibrotech makes SC to SC cords to order in Pune and tests each one.
SC to SC patch cord options
An SC to SC patch cord has an SC connector, with a square body, push-pull latch and 2.5 mm ferrule, at both ends. The larger body is easy to handle in frames and field enclosures, which is why SC remains the common connector in access networks. Radix makes SC to SC cords to order in Pune, with each option below chosen per order line. The SC connector guide explains the connector in detail.
| Option | Choices | Notes |
|---|---|---|
| Fibre type | OS2 single-mode (ITU-T G.652.D, or bend-insensitive G.657.A1 or A2); OM1 62.5/125 µm or OM2, OM3, OM4 50/125 µm multimode | Single-mode for PON and telecom; multimode for older LANs and some converters |
| Fibre count | Simplex or duplex | Simplex for PON and single-fibre converters; duplex for two-fibre equipment |
| End faces | SC/APC to SC/APC, SC/UPC to SC/UPC, or SC/UPC to SC/APC | Multimode SC is PC or UPC polished only |
| Connector colour | Green for APC, blue for single-mode UPC, beige or aqua for multimode | Adapters in frames follow the same colours |
| Jacket | LSZH, PVC or armoured | Armoured where cords are exposed to crushing or rodents |
| Diameter | 2.0 or 3.0 mm simplex; 2.0 or 3.0 mm duplex zip | 3.0 mm handles better on long frame-to-frame runs |
| Length | Any length to order | Exchange cross-connects often need long cords |
Where SC to SC cords are used
FTTH and PON
Passive optical networks use SC/APC, with its green body, through most of the optical distribution network. SC/APC cords patch feeder fibres to splitter inputs, splitter outputs to distribution fibres in the frame, and the wall outlet to the ONT in the home. The angled end face keeps reflections low, which matters most where an RF video overlay at 1550 nm shares the fibre. Many OLT PON transceivers have an SC/UPC receptacle, so the cord from the OLT port to the frame is often SC/UPC at one end and SC/APC at the other. Check both ports before ordering.
Telecom exchanges and ODFs
Exchange optical distribution frames often carry SC adapters, UPC or APC depending on the operator's standard and the age of the plant. Cross-connect cords between frames run longer than data centre cords and travel through overhead troughs, so length, jacket colour and labels matter more than diameter.
CCTV and industrial media converters
Many fibre media converters and industrial Ethernet switches use SC ports: duplex SC on two-fibre models, simplex SC on single-fibre bidirectional models that transmit and receive on different wavelengths. Camera links across campuses, car parks and plants usually run on single-mode, with multimode on older sites. Match the converter's fibre type, and on bidirectional links confirm that the units at the two ends are a complementary pair.
Older enterprise patch panels
Buildings cabled before LC became the default often have SC duplex panels, frequently on OM1 or OM2 multimode. Replacement cords must match the installed core size, since 62.5 µm and 50 µm fibre do not mix without high loss. Where new LC equipment meets an old SC panel, an LC to SC patch cord is the right part.
Simplex or duplex SC cords
PON is a single-fibre system. GPON sends downstream at 1490 nm and upstream at 1310 nm on the same fibre, and XGS-PON uses 1577 nm and 1270 nm, so SC to SC cords in access networks are almost always simplex. Single-fibre media converters are simplex for the same reason.
Duplex SC cords suit two-fibre equipment such as older switches, duplex media converters and enterprise panels. They are wired A-to-B so transmit meets receive; if a duplex link does not come up, reverse the connectors in the clip before suspecting the optics. Order simplex wherever the equipment uses one fibre, because an unused second leg is only clutter in a frame.
Choosing the length of an SC to SC patch cord
Measure the path the cord will follow along the tray or cable manager, not the straight line between the two ports. Add slack for a service loop at each end and for the strain relief, then round up to the next whole metre. A cord that is too short pulls on the connector; one that is too long clutters the frame and is harder to trace. Radix cuts SC to SC cords to any length to order, so the length can follow the route rather than a standard size.
| Typical run | Lengths commonly specified | Notes |
|---|---|---|
| ONT to wall outlet, or equipment to a panel in the same rack | 1 to 3 m | 2.0 mm cord is enough where it is handled gently |
| Splitter or switch to a panel in the next rack | 3 to 5 m | Label both ends |
| Cross-connect between frames in the same room | 5 to 15 m | 3.0 mm handles better on longer runs |
| Exchange cross-connects through overhead troughs | 15 m and longer | Consider armoured or LSZH jacket for the route |
State the length tolerance on each quote line, especially where cords go into fixed, numbered positions.
SC/APC and SC/UPC: why mixing them fails
An SC/UPC end face is polished with a slight dome at right angles to the fibre; an SC/APC end face is polished at 8 degrees. When the two are mated, the cores meet at an angle with an air gap between them. Loss is high, typically several decibels, the reflection is poorly controlled, and the spring force pressing mismatched faces together can chip both. An APC connector pushed into a UPC adapter will usually latch, so the mistake is easy to make and only shows up when the link is tested.
Colour is the first check: green bodies and adapters are APC, blue are single-mode UPC. Specify the polish at each end separately, and where the two ports differ, order a hybrid SC/UPC to SC/APC cord instead of forcing a match. The UPC vs APC guide sets out the differences in full, and the single-mode vs multimode guide covers the fibre side.
SC/APC and SC/UPC at a glance
| Property | SC/APC | SC/UPC |
|---|---|---|
| End face | Polished at 8 degrees | Polished at right angles, slightly domed |
| Body colour | Green | Blue for single-mode |
| Return loss, industry figure | 60 dB or better | 50 dB or better |
| Typical use | FTTH and PON distribution, RF video overlay, exchange frames | OLT transceiver ports, media converters, single-mode links where the equipment is UPC |
| Mated with the other type | High loss and risk of damage | High loss and risk of damage |
Testing SC to SC cords
Radix tests each SC to SC cord before dispatch. Single-mode cords are measured for insertion loss at 1310 and 1550 nm and for return loss; multimode cords for insertion loss at 850 nm and often 1300 nm. APC cords are measured with APC reference leads, since a UPC reference would itself be a mismatch. End faces are inspected under magnification against IEC 61300-3-35 criteria.
Widely used industry figures for return loss are 50 dB or better for UPC and 60 dB or better for APC. For PON work, ask for the maximum insertion loss per connector in the quote and count every connection in the optical budget for the splitter ratio. In service, contamination is the commonest fault, particularly at ONT ports handled by installers, so inspect and clean each end before it is mated.
What to put in an SC to SC quote
List each configuration on its own line, with:
- fibre type, and G.657 bend-insensitive fibre if routing is tight
- simplex or duplex
- polish at each end: APC, UPC or hybrid
- jacket and outer diameter
- length and tolerance
- labels, such as frame and port references
- test report format
- quantity for that line
Send the list through the request a quote page. Other connector pairs are on the fibre optic patch cords page.
What changes the price of an SC to SC cord
SC to SC prices are quoted on request against the list above. The main factors are:
- Polish. APC and hybrid cords take more process time than UPC.
- Fibre. Bend-insensitive G.657 and OM4 fibre cost more than G.652.D or OM2.
- Jacket. Armoured cords cost more than LSZH or PVC.
- Length. On long exchange cross-connects the cable becomes a large share of the cost.
- Paperwork. Per-cord reports and serial labels add handling.
- Volume per configuration. Many identical cords cost less each than many different ones.
Questions buyers ask
Which SC cord goes into a green ONT port?
A green port is SC/APC, so the cord needs an SC/APC connector at that end. The other end depends on the wall outlet or splitter port, which in most FTTH networks is also SC/APC. Do not push a blue SC/UPC connector into a green port.
Are SC to SC patch cords for FTTH simplex or duplex?
Simplex. PON carries both directions on one fibre at different wavelengths, so one fibre with a connector at each end is enough. Duplex SC cords are for two-fibre equipment such as older switches and duplex media converters.
Can I use a multimode SC to SC cord on a single-mode media converter?
Not reliably. The converter is designed for 9 µm single-mode fibre, and a multimode cord creates a core mismatch and high loss where it meets the single-mode cable. Check the converter label or datasheet for fibre type and wavelength, then order the cord to match.
What should the test report for an SC/APC cord show?
Insertion loss for each connector at 1310 and 1550 nm, return loss, the reference method used and the end-face inspection result. The serial number on the cord label should match the report so each result can be traced to its cord.
Does an SC to SC cord join two cables in an ODF?
A cord connects two ports; the adapters in the frame are what join connectors. To cross-connect two cables terminated on SC adapters, a cord runs from a port on one panel to a port on the other, and its polish must match both adapters.
What length of SC to SC patch cord should I order?
Measure the route the cord will follow along the tray or cable manager, add slack for a service loop at each end, and round up to the next whole metre. Radix cuts SC to SC cords to any length to order, so the length can follow the route instead of a standard size. State the length tolerance on the quote line.