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What Do The Lights On An ATA (Phone Adapter) Mean?


What Do The Lights On An ATA (Phone Adapter) Mean?
If you have a VoIP subscription at home or in your small business that you use with normal phone sets, then you must be using an ATA (analogue telephone adapter), commonly called a phone adapter. The lights that show on the side of the adapter are not there for fancy but mean a lot of things, and are here to help you read the behavior of your adapter. Each small light is called an LED, which stands for Light Emitting Diode.

The Colors

The LEDs can be of either red, yellow or green color, when they are not off. In some cases, blue replaces green. Yellow, or orange as some like to say, or even amber, if you want more traffic-like language, is rather rare, and it sometimes means that while the necessary initialization has been not been successful. Also, the lights can either be steady or blinking.

The LED Labels

Generally speaking, an ATA has four of these lights. There are of course exceptions, some have more and some less. The lights give indication on power, Internet connection, Ethernet/LAN connection and on two phone lines. If you ATA has wireless functionality, there will be one light for wireless connection.


The light for power is normally found at the end of the light array. When the adapter is powered on, it lights red for some minutes, during which the adapter initializes itself and does a power on self test. Then it lights green, which shows everything works fine with the power. If the light keeps on being red, or if it blinks, it means there is a problem with the Internet connection. If it goes yellow, your adapter has not been able to properly configure.


The Ethernet LED lights up when your adapter is connected to a network through the RJ-45 Ethernet port. This could be a direct connection to your Internet router or to your local area network (LAN) over which Internet connection is shared. This LED flashes whenever there is traffic through that port.

Phone 1

The Phone 1 port is where you plug an RJ-11 cable to connect your telephone set to the adapter. The LED lights green if your phone line is well registered with your provider and is working. It flashes whenever you make or receive calls.

Phone 2

This remains unused unless you have a second phone line from your VoIP provider or a fax service running. The connection is similar to the Phone 1 port, and the light color and patterns as well.


Some ATAs act as routers themselves, and are also used to connect you directly to the Internet through an ADSL port, which accommodates and RJ-11 (telephone line) jack. The Internet light is often labeled with Internet, ADSL or @. It lights green only when there is an Internet connection. The green light blinks whenever there is traffic through that port of the adapter over that Internet line.


If you have a wireless adapter, there will be an additional light that will be on when the connection is good, and blink whenever there is wireless traffic.

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