wired connections – jacks, plugs and adapters

By Andrea Kaneb

wired audio connection to a tv using an audio splitter to remote mic and external speaker and captions on phone

Wired connections offer straightforward and reliable access to audio. Plugging in gives you the high quality sound you need to hear people, music, movies, and news. It is cleaner and stronger audio than sound from speakers that are across the room. It also lets you split audio when you need to use it in more than one way at the same time. For example, to transmit sound (stream) to hearing aids and use a speech-to-text app at the same time. Some people are more comfortable with wired audio connections. Other people don’t have wireless capabilities. The main disadvantage is that it keeps you tethered to devices.

AUDIO OUT and AUDIO IN

For a wired audio connection, your goal is to send sound from a device to your ears. To do so, you take AUDIO OUT from a device and send AUDIO IN to some kind of “listening system”.

AUDIO OUT – the device you want to listen to:
- phone, computer, tv, music player, etc.
AUDIO IN – the device that helps you listen. This is part of a “listening system”:
- a headset, headphones, earbuds, TV connector base station, a remote mic charging station, a TV transmitter, a hearing aid streamer, a remote mic with a headphone jack, an induction neckloop, etc.

To tap into audio, you need to:

first locate the jacks on the AUDIO OUT device
next, investigate the jacks and plugs used by your “listening system”
lastly, find the correct plugs and adapters to connect one to the other.

It’s simple if you keep a few things in mind about compatibility…

Jacks and Plugs

A plug and a jack, or socket, are like two interconnecting puzzle pieces. They need to line up with each other to make an electrical connection. With wired audio connections, sometimes there is a compatibility issue. Even when a plug fits into a jack, it may not have a compatible electrical connection. If you cannot hear sound as expected, consider the audio plug. There are slight differences that depend on use.

Splitters

In the photo above, I used a splitter because I needed audio for more than one use. I plugged in a transmitter (a streamer) for audio straight to my hearing aids. In addition, I plugged in an external speaker for another person to listen in. That external speaker also provided audio for a speech-to-text app listening in on my mobile phone. Some people might call this “kludgy” and I’m okay with that.

Adapters

Sometimes the jacks and plugs on an AUDIO OUT device and “listening system” don’t fit together. In this situation, you need an adapter. An adapter is an interface. It has the correct jack or plug for the first device on one end and the correct jack or plug for the second device on the other end.

Scroll down for photos and brief descriptions of jacks, plugs and adapters:

3.5 mm (1/8″) audio jacks, plugs and adapters
- On mobile devices, you may (or may not) have a 3.5 mm headset jack
television connectors and adapters
- On televisions, look for AUDIO OUT via optical (TOSLINK), RCA or 3.5 mm
computer connectors and adapters
- On computers, laptops and tablets, audio ports include 3.5 mm jack and USB (sometimes others too)
HDMI audio & video connectors and adapters
- On projectors and other devices displaying video
landline phone connectors and adapters
- Landline phones have an RJ9 socket and some have a headset jack

3.5 mm (1/8") audio jacks, plugs and adapters

The 3.5 mm jack, also known as a headphone or headset jack, is common on most devices, except for many newer phones. It has been pushed aside by Bluetooth and yet it still holds such a simple and valuable connection.

Headset jack adapters

These bring back the audio jack that disappeared off many mobile devices. It has the same plug as your charging cord and you plug it into your phone the same way.

3.5 mm female to lightning adapter (for newer iPhones)
3.5 mm female to USB-C adapter (for some Android)

Basic splitter

– A basic audio splitter gives you two jacks so you can plug in two things that need audio at the same time. Search for a 3.5 mm Stereo Male to Two 3.5 mm Stereo Female Splitter

Headset splitter

Other splitters separate/merge audio for microphone (talking, usually colored pink) and headphone (listening, usually colored green).

Plug differences

The plugs have various tips based on their use:

mono
stereo
microphone + stereo

Technical details for plugs

The plugs are made up of parts called tip, ring and sleeve for various electrical connections.

how a plug makes a connection inside your device

When you insert a 3.5 mm plug into a socket, they connect at various places along the plug, as shown in this example.

If your audio isn’t working, you might have a plug that’s incompatible with the socket.

Socket differences that require a TRS-TRRS adapter

My computer audio jack or socket only recognizes TRS plugs, so I need an adapter for my TRRS microphone in order for it to work.

My phone only recognizes microphones with a TRRS plug, so I need an adapter for any TRS audio input. (TRS for audio output works fine.)

Audio cords

The standard audio cord has a stereo (TRS) male plug on both ends. (Any color is fine.)

Plug sizes

Audio plug and socket size is usually 3.5 mm on computers, mobile devices, TVs and handheld receivers in public venues. Some devices like the Phonak MyLink and some landline phones have a 2.5 mm socket, so a standard 3.5 mm plug won’t fit. This requires a 3.5 mm socket to 2.5 mm plug adapter (sometimes one is included with purchase).

Musical equipment uses a larger 1/4″ plug.

TRRS plug compatibility

In case you are not confused enough already, there are different TRRS plug configurations. Most TRRS plugs today are CTIA. Apple uses their own version of CTIA, so some made-for-iPhone headsets are incompatible with other devices. It’s a bit hit-or-miss. Some older products used OMTP, especially Nokia.

So, if your headset doesn’t work, it may be a compatibility issue.

television connectors and adapters

Televisions use optical (TOSLINK), RCA, a 3.5 mm headphone jack or HDMI.

Optical (TOSLINK) is a frequently used high quality audio connector that uses light. (don’t bend it)
RCA is also high quality. (red and white are audio, yellow is for video)
3.5 mm is not quite as high quality
HDMI includes video and most of our applications are for audio only

Some TVs switch off their built-in speakers when you plug something into the 3.5 mm audio socket (headphone jack). If you want to plug in a transmitter this way and other people need to hear the TV, this is a problem. While you could use a 3.5 mm audio splitter and an external speaker, it is preferable to use RCA or optical (TOSLINK) connectors because they have higher audio quality than 3.5 mm and do not disconnect the TV’s internal speakers. This way you can connect your transmitter while other people can still hear through the regular speakers.

Always connect to the AUDIO OUT socket of your TV

optical (TOSLINK) plug

optical TOSLINK splitter

This gives you two sockets so you can have two audio connections.

RCA male to 3.5 mm male adapter

You could use this to go from a TV to a hearing aid remote mic headphone jack.

computer connectors and adapters

computer ports

Wired audio connections on a computer typically used the 3.5 mm jack or a USB port.

It may be possible to split your audio for two uses. So, for example, you could stream Bluetooth audio and plug in for audio at the 3.5 mm jack at the same time. You do this by right clicking your mouse on the volume button, then using the sound control panel and stereo mix settings. Fairly complex process. Try googling it if interested.

Adapter for 3.5 mm audio and microphone to TRS plug

My computer 3.5 mm socket only works with TRS plugs and doesn’t recognize a TRRS plug. Check which plugs work in your computer or mobile device to be sure you get a compatible adapter.

Adapter for 3.5 mm audio and microphone to USB

USB Bluetooth adapter

Sometimes a Bluetooth adapter provides a more reliable Bluetooth connection than built-in Bluetooth hardware. If your devices don’t consistently connect via Bluetooth when in range, you might consider this kind of adapter, aka dongle. Be sure the Bluetooth is compatible.

Plantronics MDA 220 switch

This specialized switch made for call centers lets you switch between answering telephone calls using your office phone and computer.

HDMI audio & video connectors and adapters

HDMI cable and adapter

An HDMI cable is used for both audio and video. It is a high quality connection frequently used for television or projector.

HDMI plug, USB-C plug and lightning plug

adapters to connect a projector or tv to a mobile phone.

HDMI to USB-C adapter for many Android phones

HDMI to lightning adapter for Apple mobile devices

Be sure your adapter also has a port to plug in your charger at the same time so you don’t run out of power during a show or presentation.

landline phone connectors and adapters

RJ9 plug

This is the standard plug for a telephone handset (This is not the plug that goes into the wall).

RJ9 splitter

A splitter gives you a socket for your handset and another socket for an adapter.

RJ9 plug to 3.5 mm plug adapter

Plug the RJ9 into a handset splitter and plug the 3.5 mm into a transmitter/streamer/remote mic.

Depending on your setup, you may need to lift the handset from the cradle for each call. There are handset lifter devices as well. Make sure you have a mic on whatever you’re using too.

RJ9 plug to 3.5 mm socket adapter

Plug in a headset or other listening devices. Most wireless headsets for landline phones use DECT 6.0 instead of Bluetooth. DECT headsets operate on their own wireless channel to avoid interference. Bluetooth headsets are primarily designed for mobile phones or computers, not landline phones.

RJ9 plug to dual (audio and mic) 3.5 mm socket adapter

Use your PC headset with your CISCO office phone with a dual 3.5 mm to RJ9 plug VoIP headset adapter.

In-line amplifier and neckloop for telecoil

If you have hearing aids/CIs with a telecoil and sit in one place to use your phone, you can use an in-line amplifier combined with an amplified neckloop with built-in microphone (this one is ClearSounds), via an RJ9 to 3.5 mm male adapter. Be sure your neckloop has a built-in microphone or you’ll need to use a separate microphone.