What is the name of the connector that is similar to an RJ45 but instead of eight lines, it has ten?
The 10P10C connector is commonly referred to as an RJ50 connector, although this was never a standard registered jack in the Universal Service Order Codes. The 10P10C has 10 contact positions and 10 contacts.
The most common uses of the 10P10C connector are in proprietary data transfer systems, such as the Digiboard and Equinox Super-Serial multi-port TIA-232 adapters. 10P10C connectors are also used to implement RS-485 interfaces, and for data link connections in APC and Eaton uninterruptible power supplies. In the latter case, a keyed 10P10C plug with a protrusion on the pin 1 side near the back is used.
The RJ standards are for telephony and, though similar, are mechanically incompatible.