RJ (registered jack) adapters are devices used to convert registered jack connections from one type to another. RJ25 connectors are a standardised connection used in telecommunications applications.
What are RJ adapters used for?
RJ adapters can cover a range of purposes, depending on what type of adapter they are. Couplers join two different connectors together, using two input ports Extensions increase the range of transmission by adding to the length of cable. Adapters proper allow different connections to be joined, such as an M12 cable joining to an RJ45 connection
Types of RJ adapters
RJ adapters mainly differ in how many ports they have. They may have between one and six ports, allowing them to connect up to six cables. They can also differ in their wiring configuration, and indeed there are many different types of adapters, from feedthrough connectors to junction boxes to couplers, depending on what you need to convert between. They can be shielded or unshielded.