Plantronics CS540 Troubleshooting Guide + VIDEO - Headset Advisor

For decades, Plantronics, now called Poly, has been the global leader in headset technology for working professionals, and for those needing a headset for entertainment. Whether you need a headset with or without a wire, Poly has one that’s sure to meet, or even exceed your needs and expectations. 

One of their original wireless headsets for office workers included the models CS50, followed by its replacement, the CS55

plantronics cs50 and cs55

Both were monumental hits with sales far exceeding Poly’s expectations. Clearly this was going to be a hard act to follow with any model that would replace the CS55. In this case, the model that followed was the Plantronics CS540 convertible office wireless headset. 

plantronics cs540

How did the CS540 do as a follow-up act to the CS55 it replaced? It knocked it out of the park. The CS540 received many updates that would help to make it wildly popular across the globe.

Not only did it get a prettier face with all the cosmetic updates that all helped it to look far more contemporary over the CS55, but it had several technological improvements as well.

All told, the CS540 enjoyed a lot of popularity for a very long time. But, as with any product, it does have a shelf life and doesn’t live on forever. Still, there are countless numbers of CS540’s still in use. 

Though the CS540 has been discontinued, there’s still a need for support for those who still use them.

Many people have a need to get questions answered, and support on things that include: 

  • Setup help 
  • Echo that won’t go away 
  • Static so bad that it can make the headset unusable 
  • Battery and charging questions 
  • Remote call answering questions 
  • Placing calls on hold via the headset 
  • Headset quit working 
  • Bad sound quality

And more. 

Though this blog isn’t designed to answer every question on the CS540, it is designed to answer some of the most common ones. 

But...before I begin, I did want to let you know that I recorded a Youtube video of some of the more common issues people have when using the Poly CS540 wireless headset.

If you’re still reading, then join me as I give you some troubleshooting tips on the most common issues that customers contact us about. 

One of the most common questions we get on the Plantronics / Poly CS540 is: 


When using the headset, the person hears an echo in the ear speaker. This can not only be distracting, or even disorienting for the person wearing the headset, but it can also be very annoying to the person they're talking to. 

In most all cases, echo is caused by having volume(s) set too high. When you stop to consider that the different volumes that need to be adjust properly include: 

  1. Volume on the phone 
  2. Volume on the headset ear speaker 
  3. Volume on the headset microphone 

There’s a balance that needs to exist between all three, and when one is set too high, it’s common to experience echo. So here’s what I suggest. 

Phone volume setting 

First, double check your PHONE volume to make sure it’s set near the middle of the volume scale. You don’t want it too high, and you don’t want it too low. Kind of like Goldilocks and the three bears and that porridge, you want it just right. So, find the button that adjusts the phone volume, and make sure it’s set about halfway on the volume scale.

Headset volume adjustments 

Next, you want to turn the headset charging base upside down. Once done, you will see a couple of dials. One dial will have an icon next to it that looks like a microphone, and the other has an icon that looks like a speaker. Once you’ve located these, make sure they’re both set on the number 2. 

If either, or both of these are set too high, that can result in echo. Setting them on to the number 2 should help to eliminate that as a possible reason why you’re experiencing echo. 

A through G switch 

The next thing you can try is setting the application switch. This is located on the bottom of the CS540 charging base. You can identify this because it has a switch that can be set between settings A through G. Make sure that this is set on A. Having this on the wrong setting can result in echo and other abnormal sounds. 

Static, bad sound quality, or quit working 

If your CS540 wireless headset is giving you bad sound quality, static, or just quit working, here’s a tip that might get it working. 

Full reset 

If you perform a full reset, this can help to restore original settings which in many cases will fully resolve problems such as these. Here’s how you go about performing a full reset. 

  1. Disconnect the AC power from the CS540 charging base. You can unplug the AC cord from the base, or you can unplug the power adapter from the power outlet. Locate the battery door cover, and remove it.

    The battery door cover is located where the side of the headset meets your cheek when wearing it.

    To remove the cover apply some gentle, but firm pressure downward with your thumb, and then slide in the direction towards the end of the microphone. The cover should slide off. 

  2. Locate the battery in the compartment, and unplug and remove it. 4. Wait approximately 10-15 seconds, then reconnect the battery and slide the battery cover back into place. 
  3. Place the CS540 headset into the charging cradle. 
  4. Plug the AC power back into the CS540 charging base. 

By performing this process, you should be able to resolve several different conditions. Though these six steps may sound lengthy, it only takes a short amount of time to do the full reset, and it’s well worth it.

Battery not holding a charge 

When a Plantronics CS540 is new, it’s designed to provide you with up to 7 hours of battery life. Over time, and with many recharges, the battery will eventually give you less life. It’s not uncommon for a 7 hour battery to eventually provide only 5 hours, 3 

hours, or even less. This is normal. All headset batteries will diminish over time, and will need replacing. 

Fortunately, the CS540 has a battery that allows you to replace it. Unlike many of the models being produced today, you have the option to economically replace the battery in the CS540 yourself.

A replacement battery should cost about $20.00 to $30.00. Other headsets that don’t have a customer replaceable battery require that you replace the headset, even if the headset is in perfect working condition.

If having a replaceable battery is important to you, make sure to find out if the headset you’re considering buying has a replaceable battery or not. Knowing this you can avoid any surprises once the battery no longer holds a good charge. 

CS540 won’t allow me to answer a call when away from the desk 

We get questions about this all the time. Most people have the belief that when they buy a wireless headset, that headset should allow them to answer a call when they’re away from their desk. 

The truth is, in most all wireless headsets, you need an optional accessory in order to have remote call answering. You might need a handset lifter as shown below. 

This is a device that plugs into the CS540 headset base, and attaches to a phone. Once connected, the lifter lifts the telephone handset out of the cradle, once the call control button is pressed on the wireless headset.

After the telephone handset is taken off hook, it directs the call to the wireless headset. When the call is complete, the call control button is pressed a second time, and the telephone handset is returned to the cradle which disconnects the call. 

Other phones have ports that support a non-mechanical version of the HL10 handset lifter. These devices are referred to as EHS cables, or Electronic Hookswitch Cables. 

Example of an EHS cable being setup

Depending on the make/model of your desk phone will determine if an EHS cable is compatible. Contact us if you want help verifying compatibility.

This device operates the same as a lifter, but without the mechanics involved. Pressing the call control button allows you to access a call while away from the desk, and pressing it again terminates the call. No lifting required, as it’s done electronically. 

Whether you get a handset lifter or EHS cable, either will cost about $50.00 - $75.00 and are optional. Neither comes with the purchases of a wireless headset. So, if you use a desk phone, and want to buy a wireless headset to answer calls when away from the desk, make sure to inquire about a lifter or EHS cable. 

Have Questions? Contact us for help

And of course, contact us here at Headset Advisor if you have any questions about compatibility. We have skilled California based Advisors that can help to answer your questions. 

Companies now migrating away from Desk Phones to Softphones There’s been a steady migration away from the use of traditional desk phones, in favor of using computer based Softphones. This migration has been in play for sometime, but with the Coronavirus Pandemic, this migration accelerated. 

Two of the common questions that we get here at Headset Advisor are: 

  1. Can I use my Plantronics CS540 with my mobile phone 
  2. Can I use my Plantronics CS540 with my computer 

This is one of those situations where you say, I’ve good news, and bad news, which would you like to hear first? If you answered using your Plantronics CS540 with a mobile phone, I have to be the bearer of bad news. No, you cannot.

The reason why is because the Plantronics CS540 operates off of DECT 6.0, whereas a mobile phone uses Bluetooth when connecting to a headset. Never the twain shall meet in this case. 

On the other hand, if you had asked the question about using a Plantronics CS540 with a computer, I’d be happy to announce that yes, you sure can. Like remote call answering though, it does require the use of an optional device.

In this case, you’d be able to use the CS540 wireless headset with a computer by purchasing a Discover D315 Universal USB Adapter

All that needs to be done in order to begin using your existing CS540 wireless headset with your computer is to plug in the CS540 connector cord into the D315. Then, simply plug it into a USB port on your computer.

Simple to connect, inexpensive to purchase, and a nice way to add versatility to your CS540 wireless headset. 

If you purchase a Discover D315, connect it and then find it’s not working, you want to make sure to go into your computer sound settings to choose the D315 as the default mic and speaker.

For example, if you use windows you would go to your Start Menu > Control Panel > Hardware and Sound > Sound > Under playback and recording, click the D315 and set as default.

Can I put callers on hold using my CS540 wireless headset? 

The simple answer is no, as the wireless headset doesn’t have a way to access phone functionality via the headset. However there is a workaround that can serve the same purpose, more or less. 

When wearing the CS540 headset, there’s a small button located on the rear of the earpiece. This is the adjustment used to raise and lower the hearing volume.

Unknown to a lot of people who use the CS540, this same button is also used to mute the microphone.

This means when you’re away from your desk, and you take a call that you later want to put on hold, you can mute the microphone as you make your way back to your desk to transfer the call or further assist the caller. 

In order to mute the microphone, simply press the speaker volume button inwards and release. To unmute the microphone, press the button inwards a second time.

Though this isn’t the same as a hard hold which results in you not being able to hear your caller, and they not being able to hear you, into you being able to hear the caller, but they not being able to hear you.

You might want to read this a second time as it could sound confusing. In the end, you can likely accomplish the same thing as having a true “hold” button on your headset. 

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