What do expansion modules bring to the table? And who are they valued by?

Certainly, places and people are heavy on telephony usage. Offices that handle the high-call volume, receptionists, and call centers because they all value the extra keys and screens delivered by expansion modules.

All the extra lines are p provided. All the monitoring capabilities, too. Because maintaining a smooth workflow is everything in high-paced places.

Naturally, the value of expansion modules is reflected in the price. A single expansion module costs approximately as much as a mid-range I phone. Therefore, considering whether your business genuinely needs such extra accessories is worth considering.

We will focus on two specific expansion modules rather than the category in general: Yealink’s EXP40 and EXP50. Each is compatible with T4, T4S, and T5 series phones.

Specifically, the EXP40 can be paired with 2 different phones from Yealink’s T4 and T4S series. As for the EXP50 – it can be paired with every single one in the T5 range. 

Table of Contents


I am starting with the older of the two – the EXP40.  This expansion module is intended for the high-end range of Yealink’s T4 and T4S series.

(The phones from T4 and T4S are identical in appearance. This is why they are both compatible with the same accessories. The difference comes from the technical enhancements of the T4S series).

The EXP40 has the elegant look of its matching T4 and T4S phones. It features a 160×320 LCD screen and 20 programmable keys. There is an LED light field right next to each key.

In most cases, buttons are programmed as B-F keys. BLF stands for Busy Lam Field. These are programmable speed dials, which also show the presence of users.

However, functions other than BLF can also e said. A few that come to mind are the ‘Intercom’ function, ‘Page group’, or ‘Park call’.   

The buttons can be programmed in two ways. The first option is to press and hold the key you wish to program. A dialog box shall appear on your phone device. Then you must choose the line it responds to, the extension number, and the function it performs.  

The other way to program buttons is through Yealink’s browser based on Erface. Again, set the parameters to the button you wish and confirm. See the full instructions here.

The EXP40 also has a couple of page keys for switching between its two pages. This allows up to 40 extensions per single module.

As you can see in the image below, up to 6 EXP40 modules can be tied together on the same device. In exchange for the occupied space, this ‘daisy chain’ grants quick access to up to 240 contacts.


Perhaps the first impression of the EXP50 is the 4.3-inch color LCD screen. In line with Yealink’s T5 series, the module delivers a rich visual experience.

Like the EXP40, the EXP50 comes with 20 hard buttons and dual-col r LEDs. Unlike the EXP40, it has three dedicated buttons for switching between the pages. This allows up to 60 extensions per single module.

However, only 3 EXP50 modules can be daisy-chained. This might limit users looking for quick access to 200+ contacts.

The functionality of the EXP50 resembles the EXP40 in every aspect. There are multiple options for key programming. And just like the EXP40, the programming can be done in two ways.

Either through the phone device or Yealink’s browser-based interface (see the information above).


Each expansion module has two EXP cable ports at the back. In the first port, there goes the cable connecting it to the phone device. And in the second – the cable connecting it to the expansion module in line.  

Also, there is a connecting racket. The bracket is mounted via the screws provided in the package.

Both units have stands with 2 adjustable angles. Both are wall-mo tables. This must be good news if your Yealink devices are mounted to the office’s walls.


The following recommendation applies to both the EXP40 and EXP50.

When daisy chains more than one expansion module per phone, additional power will likely be required.

You might need additional power even with just one expansion module, especially if you use other accessories like Bluetooth dongles.  

Either way, the best practice is to get a standard 5-volt adaptor in addition to your PoE. Don’t wait until the expansion modules begin to function poorly. Being prepared is always better.  


As expected, the newer Yealink EXP50 offers a richer visual experience. Also, it extends the functionality by offering 20 extra programmable features than the EXP40.

But despite these generational differences, the EXP40 and EXP50 are two rock-solid expansion modules.

Both modules look as slick as their matching phones. Both deliver on their main functionality. Both complement their source devices handsomely.

Are there any falls? It is always somehow frustrating having to consider additional power s supplies. As the collaboration software industry matures, one would expect to worry about fewer cables and not more. But that’s about it.

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