The telephone was one of the prime innovations that mankind experienced in the 20th century. This revolutionary device made possible two-way communication at lightning speed. However, early telephones were connected with telephone lines by tapes. These connections were bungling and often break easily.
The innovation of registered jack brought a solution to this problem. A connection with registered jack was sturdy and all telecommunication companies accepted its standard format. Rj11 and Rj12 are very common jacks often used in most telecommunication systems. From the appearance, both of them look the same. For this reason, many people fail to distinguish the difference between them.
The difference between Rj11 and Rj12 is that Rj11 is a connection jack that creates a bridged connection for a single telephone line which uses flat stain cable for household wire telephone and modem connections, while Rj12 is a connection jack that enjoins central telephone system with single telephone lines through a line circuit which uses specialized RJ12 6-flat ribbon standard cables for centralized telephone network in offices.
