Glossary
Signal Standards
ASI — Asynchronous Serial Interface
A streaming data format used to carry MPEG transport streams over coaxial or fiber links. Operates at 270 Mbit/s over the same physical BNC interface as SD-SDI.
CDR — Clock and Data Recovery
A circuit inside SL Optic that extracts the embedded clock from an incoming SDI signal and uses it to regenerate a clean, jitter-free output. CDR is essential for long fiber links where signal integrity degrades — it ensures the receiving end gets a perfectly timed signal regardless of link length.
HD-SDI — High Definition Serial Digital Interface (SMPTE 292M)
The SDI standard for HD video (1080i/1080p/720p) at 1.485 Gbit/s.
MADI — Multichannel Audio Digital Interface
A serial audio standard that carries up to 64 channels of digital audio over coaxial or fiber. SL Optic detects MADI signals on BNC inputs and shows MA on the display.
SD-SDI — Standard Definition Serial Digital Interface (SMPTE 259M)
The original SDI standard for SD video (525i/625i) at 270 Mbit/s.
SDI — Serial Digital Interface
The family of professional uncompressed digital video standards defined by SMPTE. SL Optic handles the full SDI family from SD (270 Mbit/s) through 12G (11.88 Gbit/s).
SMPTE — Society of Motion Picture and Television Engineers
The international standards body that defines the SDI family of interfaces (259M, 292M, 424M, 2081, 2082) and many other broadcast engineering standards.
3G-SDI — 3G Serial Digital Interface (SMPTE 424M)
SDI at 2.97 Gbit/s, used for 1080p50/60 and some 2K formats.
6G-SDI — 6G Serial Digital Interface (SMPTE 2081)
SDI at 5.94 Gbit/s, used for some 2K and 4K formats at lower frame rates.
12G-SDI — 12G Serial Digital Interface (SMPTE 2082)
SDI at 11.88 Gbit/s, supporting 4K (UHD and 4096×2160) at all standard frame rates including 60p.
Optical Technology
BiDi — Bidirectional SFP module
An SFP module that transmits and receives on a single fiber strand using two different wavelengths. Requires a matching BiDi module with reversed wavelengths at the other end.
CWDM — Coarse Wavelength Division Multiplexing
Technology that assigns different wavelengths to different channels, allowing multiple independent signals to share a single fiber strand. CWDM wavelengths are spaced 20 nm apart from 1270 nm to 1610 nm, providing up to 18 channels per fiber.
DDMI / DOM — Digital Diagnostics Monitoring Interface
An SFP module feature that reports optical TX and RX power levels to the host device. SL Optic displays these values on Screens 3 and 4. Modules without DDMI still work but show 00001 for power readings.
Dark fiber
Installed fiber optic cable that is not currently in use (no active equipment connected). Broadcast facilities often lease dark fiber between buildings or sites for dedicated private connectivity.
SFP — Small Form-factor Pluggable
The hot-swappable transceiver module standard used for optical connections. SL Optic uses two SFP slots, each covering two optical channels. The SFP type (BiDi, dual-input, dual-output) must match the required channel direction.
Single-mode fiber (SMF)
Optical fiber with a small core diameter (typically 9 µm) that supports transmission over long distances (up to 60 km and beyond) using laser light. Required for links longer than a few hundred meters.
Multi-mode fiber (MMF)
Optical fiber with a larger core (50 or 62.5 µm) used for shorter distances (typically up to 300–500 m). Lower cost than single-mode but not suitable for the long-distance links SL Optic is primarily designed for.
Physical
BNC — Bayonet Neill–Concelman connector
The standard coaxial connector used for SDI signals in professional broadcast equipment. SL Optic uses 75 Ω BNC connectors for all four SDI ports.
IEC C14
The 3-pin power inlet connector on the rear panel of SL Optic, accepting a standard IEC C13 power cord (same as most servers and monitors).
1U
One rack unit — 44.45 mm of vertical space in a 19" rack. SL Optic occupies 1U when installed in the 3-in-1U rack chassis.
Units
| Symbol | Name | Usage |
|---|---|---|
| Gbit/s | Gigabits per second | SDI bitrate (e.g. 12G-SDI = 11.88 Gbit/s) |
| dBm | Decibel-milliwatts | Optical signal power relative to 1 mW — shown on display Screens 3 and 4 |
| nm | Nanometer | Optical wavelength (e.g. 1310 nm, 1550 nm) |
| km | Kilometer | Fiber link distance |