A duplex LC patch cord that uses one round cable instead of two zipcord halves — roughly half the volume in the cable manager.
What Is an LC Uniboot Cord?
A conventional duplex LC patch cord is two simplex cables laid side by side with a clip holding the connectors together. A uniboot puts both fibres inside a single round jacket and brings them into one shared boot, so a single cable serves the duplex pair.
The benefit is physical rather than optical. Optically it is an ordinary LC: 1.25 mm ferrules, the same insertion loss grades, the same polish options. What changes is that a rack of uniboot cords occupies roughly half the volume of the same rack of zipcord, which matters for airflow as much as for tidiness.
There is a mechanical consequence worth knowing. Both fibres share one jacket and one strain-relief path, so a pull on the cord is taken by both connectors at once and a twist near the boot loads two ferrules rather than one. Uniboot is dressed and routed, not tugged from the far end of a tray.
Switchable Polarity
The better designs let you swap the two connector bodies inside the boot on site, turning an A-to-A cord into an A-to-B without tools and without re-terminating anything. That removes a whole class of stock problem: you no longer need both polarities of every length on the shelf, and a polarity mistake found at two in the morning is a thirty-second fix rather than a trip to the store.
It is worth being disciplined about what follows. The ferrules have been handled, so they go under a probe before they go into an adapter — see end-face inspection.
Push-Pull Tabs and Dense Panels
Push-pull variants extend the latch into a tab you can pull from the front of a crowded panel. Without one, releasing a connector in a full 1U panel means reaching in and gripping the cable body, which is how ferrules get contaminated, latches get broken and neighbouring cords get unseated.
The round jacket also behaves better in a cable manager than zipcord, which tends to twist along its web and hold a bend. Most uniboot is built on G.657.A2 glass, so the tight radii inside a manager cost a fraction of a decibel rather than a fault.
Where You Meet It
High-density data-centre patching, and increasingly the default for new builds. Beyond LC, the same density pressure produces the VSFF families — MDC, SN and CS — which the uniboot and VSFF article compares. See our uniboot push-pull cords, available with switchable polarity in single-mode and multimode.
LC uniboot reference
| Cable | one round jacket carrying both fibres, typically 2.0 mm |
|---|---|
| Against 2.0 mm duplex zipcord | roughly half the cross-sectional area |
| Fibre | G.657.A2 bend-insensitive in most builds |
| Practical bend radius | set by the G.657 class — 10 to 15 mm |
| Polarity | fixed, or field-switchable without tools |
| Latch options | standard, push-pull tab, rotating clip |
| Ferrule | 1.25 mm, UPC or APC |
| Insertion loss | as any LC — 0.25 dB standard, 0.12 dB low-loss grade |
| Where it wins | switch faceplates, dense panels, airflow under the cable tray |
Related Terms
VSFF connectors, G.657, MPO polarity, insertion loss, end-face inspection.