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Quick Reference Charts

Connector pinouts, intercom wiring, SDI standards, fiber color codes, and audio levels

XLR — Balanced Audio (3-Pin)

1
Ground / Shield
Cable shield, screen, or drain wire
2
Hot / Positive (+)
Signal positive (non-inverting)
3
Cold / Negative (−)
Signal negative (inverting)
Pin 1 = Ground rule: always ground pin 1 at the destination (input) end to avoid ground loops.

TRS / TS — ¼″ Phone Jack

Tip
Signal Hot (+) / Left
Hot (balanced) or left channel (stereo)
Ring
Signal Cold (−) / Right
Cold (balanced) or right channel (stereo)
Sleeve
Ground / Shield
Common ground / return
TS (2-conductor): Tip = signal, Sleeve = ground (unbalanced only)

BNC — Video / SDI Coaxial

Center
Signal (+)
75Ω center conductor — carries video/data signal
Shield
Ground / Return (−)
Outer braid / connector body
Critical: Use 75Ω cable. Impedance mismatch causes reflections, ghosting, and signal loss. Do not use 50Ω BNC for video.

RJ45 Ethernet — T568B (Standard)

Pin 1: White/Orange
Pin 2: Orange
Pin 3: White/Green
Pin 4: Blue
Pin 5: White/Blue
Pin 6: Green
Pin 7: White/Brown
Pin 8: Brown
Pairs: 1-2 (Orange), 3-6 (Green), 4-5 (Blue), 7-8 (Brown). T568A swaps orange and green pairs.

HDMI Type A — Key Pins

Pins 1–9: TMDS Data — 3 differential pairs + clock pair

Pin 13: CEC (Consumer Electronics Control)

Pin 14: Reserved / HEC+ (v1.4+)

Pin 15: SCL — I²C clock for DDC/EDID

Pin 16: SDA — I²C data for DDC/EDID

Pin 17: Ground

Pin 18: +5V Power (50mA max)

Pin 19: Hot Plug Detect

DB9 — RS-232 Serial

Pin 1: DCD (Data Carrier Detect)

Pin 2: RXD (Receive Data)

Pin 3: TXD (Transmit Data)

Pin 4: DTR (Data Terminal Ready)

Pin 5: GND (Signal Ground)

Pin 6: DSR (Data Set Ready)

Pin 7: RTS (Request to Send)

Pin 8: CTS (Clear to Send)

Pin 9: RI (Ring Indicator)

DCE vs DTE: Pins 2&3 swapped, 4&6 swapped, 7&8 swapped. Uses: router control, PTZ, legacy device config.

DB9 — RS-422 (Sony 9-Pin)

Pin 1: Protective Ground / Shield

Pin 2: TXD− (Transmit Data Negative)

Pin 3: RXD+ (Receive Data Positive)

Pin 4: GND (Signal Ground)

Pin 5: No Connection

Pin 6: +12V Power (optional)

Pin 7: TXD+ (Transmit Data Positive)

Pin 8: RXD− (Receive Data Negative)

Pin 9: GND (Signal Ground)

Uses: VTR control, server control, legacy deck control (Sony BVW, BVU series)

GPI / GPO — General Purpose I/O

• Contact closure or voltage-based trigger (5V TTL or 12V relay)

• Active low (pull to ground) is most common for broadcast equipment

• Pin assignments are manufacturer-specific — always verify with device manual

• Common implementations: DB15, DB25, RJ45, or screw terminals

Uses: tally lights, automation triggers, switcher control, router crosspoints, device sync