RJ50 vs RJ45: Key Differences & When to Use Each Connector
RJ50 is a 10-position, 10-contact (10P10C) modular connector; RJ45 is an 8-position, 8-contact (8P8C) jack and plug that carries Ethernet signals.
Both look like plastic telephone plugs, so technicians grabbing parts from the cable bin often confuse them—especially when a thicker RJ50 cable fits into an RJ45 jack and seems to “work” until the network drops.
Key Differences
RJ50 adds two extra conductors, supports more signal paths, and is common in specialized serial or scale systems. RJ45 is standardized for twisted-pair Ethernet, PoE, and structured cabling worldwide.
Which One Should You Choose?
Use RJ45 for any Ethernet LAN. Reserve RJ50 for point-of-sale scales, lab instruments, or custom control panels where 10 conductors are needed and Ethernet compatibility is irrelevant.
Can I plug RJ50 into an RJ45 socket?
Yes, physically it fits, but pins 9-10 will float and the link will fail or behave erratically.
Are crimping tools different?
RJ45 crimpers handle 8 pins; RJ50 needs a 10-pin die—check the tool markings before buying.
Is RJ50 faster than RJ45?
No. Speed depends on the protocol, not the connector shape; RJ45 Ethernet can exceed 10 Gbps.