RJ-9,11,14,25,48
A complete guide to RJ-11, RJ-14, RJ-25, RJ-48, and RJ-9 connectors with color-coded diagrams and technical descriptions.
RJ-48 – E1 and T1 Plug (8P8C)
Connector Type: 8P8C (8 positions, 8 conductors)
Color Code: Orange, Green, Blue, Brown, White, Black
Application: Used in digital telecommunications for T1/E1 lines in carrier networks and PBX systems.
Pin Functions: Each pair (1–2, 3–4, 5–6, 7–8) carries a separate tip and ring signal for high-speed data or voice channels.
Standard: ANSI/TIA-568-B
RJ-25 – 6P6C Plug
Connector Type: 6P6C (6 positions, 6 conductors)
Color Code: White, Black, Red, Green, Yellow, Blue
Application: Designed for multi-line telephone systems supporting up to three independent phone lines.
Pin Functions: Pairs (1–2), (3–4), and (5–6) each carry a separate line (Tip/Ring).
Usage: Found in business telephony and legacy PBX installations.
RJ-14 – 6P4C Plug
Connector Type: 6P4C (6 positions, 4 conductors)
Color Code: White, Black, Red, Green
Application: Used for dual-line residential or office telephones.
Pin Functions: Pins 1–2 for Line 1 (Tip/Ring), Pins 3–4 for Line 2 (Tip/Ring).
Note: Compatible with standard RJ-11 jacks when only one line is used.
RJ-11 – 6P2C Plug
Connector Type: 6P2C (6 positions, 2 conductors)
Color Code: White, Red
Application: The most common connector for single-line analog telephone service worldwide.
Pin Functions: Pin 1 = Tip (T), Pin 2 = Ring (R) – carries the voice signal and power for the phone.
Compatibility: Widely used in home phones, fax machines, and modems.
RJ-9 – 4P4C Plug (Inside the Handset)
Connector Type: 4P4C (4 positions, 4 conductors)
Color Code: Black, Red, Green, Yellow
Application: Connects the handset to the telephone base, carrying microphone and speaker signals.
Pin Functions:
- Pin 1 (Black): Ground / MIC return
- Pin 2 (Red): Microphone (MIC)
- Pin 3 (Green): Speaker (SPKR)
- Pin 4 (Yellow): Ground / SPKR return
Internal Circuit: Often includes a ~500Ω resistor between MIC and SPKR to prevent feedback oscillation.
