T21P E2 and power adapters

[Mauro]

Hello!
I wanted to ask if the standard equipment of "T21P E2" includes the power adapter, as I find some suppliers which say that power adapter is not included and I wanted to understand if that's always the case or not.

Also, since I have many unused power adapters from old "T20P" and "T22P" phones... are they compatible with "T21P E2"?

[Aishion_Yealink]

(02-27-2018 02:40 PM)Mauro Wrote:  Hello!
I wanted to ask if the standard equipment of "T21P E2" includes the power adapter, as I find some suppliers which say that power adapter is not included and I wanted to understand if that's always the case or not.

Also, since I have many unused power adapters from old "T20P" and "T22P" phones... are they compatible with "T21P E2"?

Dear customer,
​
​This is Aishion from Yealink technical team, nice to know you. My pleasure to work for you!
​
The Power Adapter standard equipment of "T21P E2" is optional since this model support POE feature, you can order PSU or not.

The unused power adapters from old "T20P" and "T22P" phones are can't work with "T21P E2" since it's different output standard(larger output may damage the phone itself), you can kindly see below:

T20P or T22P: AC 100~240V input and DC 5V/1.2A output

T21P E2: AC 100~240V input and DC 5V/600mA output

For more information about T21P E2, please kindly refer to below datasheet:

http://download.support.yealink.com/down...et_V81.pdf

​Any question, please feel free to contact us.

Best Regards

Aishion

[Mauro]

Excuse me, I'm not an expert about the topic, but isn't it the voltage that has to be EXACTLY the same (both have 5V), while Ampere have to be the same OR ABOVE?
Aren't more Ampere in a PSU a good thing, usually? I thought a PSU could supply any Ampere (at a specific voltage) up to its maximum amount, which is the one written on it.

It's logic that you cannot use a T21P E2 PSU in a T20P due to the T20P probably requiring MORE than 600mA... but I guess the opposite should work (IF the connection "jack" is the same, of course... IS IT?), as T21P E2 consumption has to be less than 1.2A.

Just like the PSU of a PC... the fact that it supports up to 500W does not mean that you machine MUST consume 500W all the time! Isn't it?
Or like if you have a top-level cell phone PSU which has got 2A, you can still use it also to recharge an entry-level cell phone which original PSU was only 1A... isn't it?

[Aishion_Yealink]

(03-02-2018 11:28 AM)Mauro Wrote:  Excuse me, I'm not an expert about the topic, but isn't it the voltage that has to be EXACTLY the same (both have 5V), while Ampere have to be the same OR ABOVE?
Aren't more Ampere in a PSU a good thing, usually? I thought a PSU could supply any Ampere (at a specific voltage) up to its maximum amount, which is the one written on it.

It's logic that you cannot use a T21P E2 PSU in a T20P due to the T20P probably requiring MORE than 600mA... but I guess the opposite should work (IF the connection "jack" is the same, of course... IS IT?), as T21P E2 consumption has to be less than 1.2A.

Just like the PSU of a PC... the fact that it supports up to 500W does not mean that you machine MUST consume 500W all the time! Isn't it?
Or like if you have a top-level cell phone PSU which has got 2A, you can still use it also to recharge an entry-level cell phone which original PSU was only 1A... isn't it?

Dear customer,

Thanks for your prompt reply.

For your question, yes you can successfully power on the T21P E2 using T20P PSU.

But we can't tell that the PSU can work with T21P E2 since it may caused some potential problem such as decrease device lifetime.

Hope you understand and have a nice day!

Any question, please feel free to contact us.

Best Regards

Aishion