RJ 45 and RJ 48 are two similar wirings or connectors, they use similar modular connectors, and it is not easy to identify the difference between them. Unlike if it comes to differentiating between RJ 11 and RJ 45 or RJ 48, that is actually easier to do. RJ stands for Registered Jack, and the major difference between these two entities in the discussion is their wiring. Both RJ 45 and RJ 48 use 8P8C modular plug with two pairs of the wires; one pair transmit data the other pair for receiving data.
The common RJ 45 uses the pins 1,2,3, and 6 to receive and transmit data. For RJ 48, the configuration can be used. A configuration can use the pins 1,2,4 and 5, and another configuration can use pin 1,2,7 and 8. The RJ 45 is popular in homes and offices as it is used majorly in a local area network where the network element's distance is short. The RJ 48 is used mostly in T1 data lines and other applications where the wires extend to long-distance, and it's exposed to the environment.