|  | 5.4 | Layer 1 Components and Devices
| 5.4.6 | Transceivers
A transceiver is a combination of transmitter and receiver. In networking applications, this means that they convert one form of signal to another form. For example, many networking devices come with an auxiliary unit interface and a transceiver that allows a 10Base2, 10Base5, 10Base-T, or 10\100 Base-FX to be connected to the port. A common application is the conversion of AUI ports to RJ-45 ports. They are Layer 1 devices. They transmit from one pin configuration and/or media to another. Transceivers are often built into NICs, which are typically considered Layer 2 devices. Transceivers on NICs are called signaling components, which means they encode signals onto the physical medium.