Q. Should I buy Single-mode (OS2) or Multimode (OM3/OM4/OM5)?
A. Single-mode is used for long distances measured in kilometres. It has a tiny 9 µm core that carries light in a straight line. Multimode is used for short distances under 400 metres, typically inside a building or server rack. It has a larger 50 µm core allowing light to be transmitted in multiple "modes". Your choice may be limited by existing equipment or cables. You cannot join single mode to multimode.
Q. What is the difference between OM3, OM4, and OM5?
A. OM3 supports 10Gb up to 300 metres. Om4 supports 10Gb up to 400 metres and 100Gb up to 100 metres. OM5 is designed for "Shortwave Wavelength Division Multiplexing" (SWDM), allowing higher speeds over fewer fibres. OM3, OM4 & OM5 are all backwards compatible. You can only rely on the spec of the weakest link. An OM5 lead with work with an OM3 lead but your spec reduces to the OM3 values.
Q. What re the differences between the connectors?
A. All connectors do the same job. They enable accurate alignment of the cores within the two mating fibres, usually through an adaptor. The most common connectors at the moment are LC, SC & MTP. LC's are a small connector that has a latch on the top <pic>. SC's are a square connector that has a push/pull case <pic>. The MTP carries multiple fibres, 12 or 24, in a single connector. They are commonly used in data centres where space is at a premium. All these connectors are available in both multimode & single mode versions.
Q. What is UPC and APC?
A. This related to the shape of the tip of the ferrule within the connector. A UPC ferrule looks flat to the eye. This is suitable for most applications. UPC connectors are typically blue for single mode or aqua/heather violet for OM3/OM4. APC connectors are mandatory for CATV, GPON and long-haul single-mode applications. These are typically green.
Q. What are plenum and riser leads?
A. Plenum and riser are terms use in the USA. Plenum is used in air voids and underfloor spaces. Risers are used for vertical links between floors. The European equivalent are "Low Smoke Zero Halogen" (LSZH). Although they focus on similar properties, they are not directly comparable. In Europe, check your CPR rating requirements when buying LSZH leads.
Q. What is the difference between "Armoured" and "Tactical" cables?
A. Buyers ask this for outdoor or industrial installs. Armoured cable has a metal layer to prevent rodent damage or heavy wear, while Tactical cable is designed to be stepped on or run over by vehicles. Tactical is better suited to temporary installations.
Q. How should i clean my connectors?
A. If you are not familiar with fibre, you are better to leave connectors in place. If you touch the fibre end face you with leave oils from your hands, dust and potentially scratch your fibre. If you need to clean your connectors you can use a cleaning cassette <link> or a cleaning pen <link>. You can also use an IPA alcohol wipes <link> but you need to be careful about residue. It is standard industry practice to inspect the end face after cleaning which requires a scope. Never view life fibre through a manual scope. Use a digital probe instead.
Q. Can i trust a new lead out of the packet to be clean?
A. The short answer is no. No matter where you buy from, moisture oil & dust can remain on the fibre from manufacture. As an industry standard, always inspect, clean and inspect again before mating to another lead or device. If you miss this step, you risk two dirty connectors and potential damage once the fibre goes live. When inspecting a live fibre never look directly into the fibre or view through a manual scope. Never wipe the connector with your finger or use a non approved cleaning product.
Q. What is a fanout?
A. Some situations require connections between MTP to LC for example. To achieve this the cable passes through a breakout where you transition from a single cable containing 12 fibres into 12 tails containing 1 fibre each. This whole assembly is called a harness or fanout.
Q. What are adaptors for?
A. Adaptors allow two connectors to align together allowing the signal to pass from one lead into another. The adaptor will have a way to fix itself to a plate with a cut-out in it. This plate can be in a wall box, a din box, a patch panel or other management device. The cut-out is called a 'footprint' and is normally SC Simplex or SC Duplex. For example, an LC Duplex adaptor will fit into an SC simplex footprint.
Q. What do colours mean in fibre optic patch leads?
A. Cables can be made in any colour. While you might like to choose, sticking to the industry standards is wise. OM1 is Grey, OM2 is Orange, OM3 is Aqua, OM4 is Heather Violet, OM5 is lime green, Single-mode is Yellow. There are other colours for example, PM fibre is usually Blue.
When looking at connectors, Beige covers all multimode, OM3 is also Aqua, OM4 is also Heather Violet, Single-mode UPC is Blue, APC is Green. These colours can be on the connector body, boot or both.
Pigtails and bare fibres come in 12 colours. These are ordered Blue, Orange, Green, Brown, Grey, White, Red, Black, Yellow, Purple, Pink, Cyan. Additional sets of 12 are banded to identify sets.