Inspirion 3543 - question about combo jack

Question 1: Is it enough to me for this purpose an ordinary splitter headset - 2x jack ?

Hello. The combo jack socket on the Inspiron 15 3543 is meant to be used with either standard stereo headphones, or with a headset (stereo headphones with a built-in mono mic).

In theory, a splitter or adapter with a TRRS plug (tip/ring/ring/sleeve) can be used with a combo jack socket. A TRRS plug looks like this:

However we have received a lot of posts from people who say that the adapter did not work for them. Some people have posted and said that the adapter did work for them.

Note that the input of a combo jack socket is mono. There is no way to make it be a stereo input.

Question 2: Is this laptop can adjust the mic input on the Line in ?

You can adjust the mic input volume in the Sound properties (Control Panel>Sound). Open the Sound properties, then click the Recording tab at the top. Right click on Microphone. Click "properties". Select the Levels tab at the top to find the sliders to adjust the mic input volume.

It is similar to this picture except you would click on "Levels", not "Listen".

I understand i have to purchase of outer sound card with the input line ?

It depends on what you are trying to do. If you are trying to use a microphone with a TRS plug then you can use a usb audio jack. A TRS plug looks like this:

A usb audiio jack looks something like this:

A usb audio jack is inexpensive, costing $5 - $10, but the mic input is mono. If you need a stereo line-in input, then you need to get a more expensive audio interface that has a line-in jack. Here is a picture of a device made by Behringer, that has dual mono (stereo) line-in jacks. Note that on this product the jacks are the RCA type.

In the US that device costs $29.