Is there a way to connect a cell phone line or sim card into a office phone system?

I have done this before with VOIP however I'm unsure how to do this with a cell phone signal.

I was wondering if perhaps there was something with a antenna, sim card slot and maybe a phone output jack which I could use to incorporate into my phone system or traditional phone line.

Does such a device exist?

Thanks.

Check this product out:

Xtreme Technologies Xlink BTTN Bluetooth Gateway-Black

I'm using one connected to a 1A2 key telephone system to make and receive calls from my iPhone.

The few times we have had to do this we have had success with products from Multitech.

While a Google search shows there are many devices out there, I am not sure how well designed they are. Multitech has always proven to be rugged, works, and offers great tech support. Email them and I am sure they will respond. ~ Mike

www.multitech.com