There are three basic transceiver types used for RS-422 and RS-485. The most commonly used is the 8-lead half duplex version in which the driver outputs and receiver inputs share pins on the package which eases the interface to a single, bidirectional cable. The A/Y pin – which is sometimes referred to only as “A”- is the non-inverting terminal, while the B/Z (sometimes just “B”) pin is the inverting terminal. There is also a driver enable pin to allow multi-point operation and a receiver enable pin for echo suppression which prevents transmitted data from being received by its own receiver. The next most commonly used transceiver is the 14-lead full duplex type, where the driver outputs and receiver inputs are bonded to separate pins for connection to separate busses. Industry standard full duplex pin notations are A and B for the non-inverting and inverting receiver inputs, and Y and Z for the non-inverting and inverting transmitter outputs. The Tx enable pin allows for use in both full duplex RS-485 networks and single driver RS-422 networks. Some 14-lead devices have Vcc connections on both pins 13 and 14, while others have only pin 14 as shown on this slide. In the latter case, pin 13 has no internal connection so it is acceptable to also have Vcc connected to it. Many of Renesas' families also offer this transceiver in a 10-lead MSOP for space constrained applications. The third transceiver type is the 8-lead full duplex version with no enables. Without the driver enable pin, this transceiver configuration is useful for only single driver, RS-422 type busses.