Copper Cable Termination & Pinout Guide
Copper Cable Termination & Pinout Guide
Interactive wiring diagrams for serial and Ethernet cables. Select a connector type and cable standard to see the complete pinout with color-coded wiring.
| Pin | Color | Signal |
|---|
| Pin | Color | Signal |
|---|
Notes
Cable Reference Guide
RJ45 Ethernet Cables
T568B Straight-Through
Most common standard in North America. Connect switch to PC, router to switch. Both ends identical.
T568A Straight-Through
Government/military standard. Both ends identical. Compatible with T568B devices.
Crossover
Connect like devices: PC to PC, switch to switch. One end T568A, other T568B.
Rollover (Console)
Cisco console cable. Pin 1 connects to pin 8, pin 2 to pin 7, etc. Used with console adapter.
RS-232 Serial Cables
Null Modem
Direct connection between two DTEs (e.g., two PCs). Crosses TxD/RxD and handshaking signals.
Straight-Through
DTE to DCE connection (PC to modem). All pins connect 1:1.
Loopback
Testing adapter. Connects TxD to RxD and handshaking signals to allow self-test.
Cisco Console
RJ45 rollover cable + DB9 adapter. Standard for Cisco/Juniper device management.
Wire Color Standards
T568B (most common): White/Orange, Orange, White/Green, Blue, White/Blue, Green, White/Brown, Brown
T568A: White/Green, Green, White/Orange, Blue, White/Blue, Orange, White/Brown, Brown
Note: The key difference between T568A and T568B is that pairs 2 and 3 (orange and green) are swapped.
Common Applications
- Network devices: T568B straight-through for most connections
- Cisco console: Rollover cable (light blue) with RJ45-to-DB9 adapter
- Legacy serial: DB9 null modem for direct PC-to-device connections
- Testing: Loopback adapters for verifying port functionality