2.5mm Headset Common Issues and Fixes

In this post, we talk about 2.5mm headset common issues and fixes. Using a 2.5mm headset, people may experience problem like, no sound out from the headset, static or voice not stable. Some customers thinking the headset is defected; the headset’s quality is bad. Is it true? Let us list the most common issues, find out the reason and fix them.  

Issues: No dial tone / Noise / Cut in & out

Connected the headset’s 2.5mm connector to the phone, press the headset key, but can’t get dial tone on the headset speaker. The headset works, but there are noise, sometimes the headset voice cut in and out.

To find out what cost these problems, let’s see how does 2.5mm headset connector work.

How 2.5mm headset connector works?

2.5mm headset connector is a round pin connector in 2.5mm diameter, 14mm long and with 3 conductors separated by 2 black insulators. These 3 conductors connect to the headset’s speaker and microphone as the image below.

2.5mm headset connector
2.5mm Headset Connector

In the other side, the telephone 2.5mm headset jack has 3 corresponding conductors as the following image.

What happen if these corresponding conductors not touch?

2.5mm Headset Common Issue 1

The tip of the 2.5mm connector may not be able to touch the microphone+ conductor of the headset jack.

2.5mm headset common issue 1, Connector doesn't touch wiht the microphone conductor pin in the 2.5mm headset jack diagram
2.5mm Connector doesn’t touch wiht the microphone conductor pin in the 2.5mm headset jack

2.5mm Headset Common Issue 2

Or, the headset jack’s speaker+ pint may not touch the 2.5mm connector’s speaker + conductor.

2.5mm headset common issue 2, connector speaker+ conductor doesn't touch 2.5mm headset jack's speaker pin diagram
2.5mm headset connector speaker+ conductor doesn’t touch 2.5mm headset jack’s speaker pin

The length of a 2.5mm headset connector is only 14mm. It is not easy to tell by looking at the connector if the connector is all the way in or only 13mm or 13.5mm into the jack, especially if the jack is deep like the left phone on the image below.

Desktop phone's 2.5mm headset jack
The 2.5mm headset jack on the left phone is deep inside

How to fix these issues?

It is simple; make sure the 2.5mm headset connector is all the way into the headset jack as image below. 

2.5mm headset connector plugged into headset jack correctly diagram
2.5mm headset connector plugged into headset jack correctly

The microphone and speaker conductors inside the 2.5mm headset jack are little springs. When the speaker passed the 2.5mm connector tip, there will be a little click sound. When the microphone conductor passed the connector tip, there will be another click sound. Make sure hear two clicks sound. Some phone’s 2.5mm jack may be tighter at new. In this case, we need to push the 2.5mm connector harder until hear two clicks sound.

With the 2.5mm headset connector fully plugged into the 2.5mm headset jack, problem like no sound, static and voice cut in and out will be gone.

Another Issue: 2.5mm connector does not stay in the headset jack

Reason 1: the connector is not into the headset jack enough

The microphone and speaker conductors inside the 2.5mm headset jack are little springs. These two springs are in opposite direction. Together these two springs hold the 2.5mm connector tide inside the headset jack once the 2.5mm connector fully plugged into the headset jack.

Reason 2: The jack is not a 2.5mm jack.

In North America, home phones and home office phones use 2.5mm headset jack. Other countries, like in Asia, they may use 3.5mm. In some case, people try to use a 2.5mm headset with a smartphone. But smartphones use 3.5mm jack, not 2.5mm. With 1mm space, 2.5mm connector will not stay in a 3.5mm jack.

Using 2.5mm headset with Computer?

There are many different configurations on computer audio jacks. Some computers use 3.5mm jack. Some use 2.5mm jack but separated speaker jack and microphone jack. For computer, we suggest customers use USB headset instead. Please read our post “How to use your telephone headset with a computer“.

There are some desktop phone brands and models use 2.5mm headset. Like Allworx 9100 IP Phone series, Cisco SPA Small Business series phones, Polycom SoundPoint IP phones older models, AT&T, Panasonic Home Office phones.

We talk about 2.5mm headset some common issues and fixes on this post. If you experienced different type of issues when using 2.5mm headset, please share with us. We’ll do our best to solve the issue for you.