I need top use one jack for internet and a landsline wired telephone, is this possible? Do I need some sort of splitter?

If you have a single incoming land line you can't use it for internet at the same time you are making/receiving a call.

iofast » Telephone » DSL Filters » DSL Splitter (Line 3 & 4) (http://www.iofast.com/product_info.php/products_id/1921?gclid=CPCQ4tX987ICFQfonAodM3gAIw)

When I got my adsl router/modem from SBC (2Wire) it came with several filters that were to be used on each phone or fax machine in the house so you can use them without the internet and phone messing with each other. But later, when I had a tech from the phone company (AT&T) out at the house, I mentioned to him I had heard of a filter that can be installed outside to cover all inside devices. He just happened to have one in his truck and now I have a bunch of filters I don't need. It might cost a little (mine was free) but that's the way to go. You still need a splitter if you want the PC and a phone from the same jack.

When I got my adsl router/modem from SBC (2Wire) it came with several filters that were to be used on each phone or fax machine in the house so you can use them without the internet and phone messing with each other. But later, when I had a tech from the phone company (AT&T) out at the house, I mentioned to him I had heard of a filter that can be installed outside to cover all inside devices. He just happened to have one in his truck and now I have a bunch of filters I don't need. It might cost a little (mine was free) but that's the way to go. You still need a splitter if you want the PC and a phone from the same jack.

I agree, I always use Whole House splitters, and use the last pair(Brown/white pair) for DSL.
Looks a lot better without the Filters.
I leave the orange and green pair for a second line and/or 31X Return?