What are Modem Lights?
If you have an external modem, those flashing or steady lights tell you what’s happening in the ongoing ‘handshaking’ or interaction between your computer (with its Universal Asynchronous Receiver / Transmitter or UART microchip) and the modems. Or, more formally, to use the RS-232C serial standard terms, between the Data Terminal Equipment (DTE) interface and the Data Communication Equipment (DCE) interface.
Modem lights are simply the lights that are found on external modems. Depending on whether the lights are dark, activated and steady, or flashing, each modem light will provide an indication of the activity that is currently taking place between the modem and the connected computer hard drive. The current status of the modem lights helps the end user to know whether a connection is established, if the connection is active, or if the connection has dropped for some reason. The activity of modem lights is usually referred to as handshaking. Essentially, when the modem is in use, the device is interacting with the computer. The modem receives input from the computer and in turn provides the hard drive with an influx of data as well. Both devices confirm receipt of data received and commands issued by the other. In this sense, the handshake is not unlike a gesture between two individuals who have agreed to an exchange or a plan of action. This interaction or handshake that is signified by
