USB headset to RJ11...

[carnageX]

This is the headset he is referring to:
Razer Carcharias - Gaming Headset | Razer Online Store

I don't know what you mean when you say that "there's no usb sound card inside" the headset...

 

[patonb]

He's saying you need some form of ssound card to get the digital headephones to connect to the analog telephone.

 

[JDGreen92086]

Upon further review it seems the headset is NOT USB! It has mic and headphone 3.5 mm jacks. My old headset was a USB headset and this is fairly new... I apologize. I believe I found EXACTLY what I'm looking for... The Headset Buddy. On some websites it doesn't have great reviews, but I'm going to speak to a rep and ask some questions. Fortunately the CISCO phone is the exact phone we have at the call center. The page lists all the CISCO VoIP phone models that this product will work with.

Sorry for the confusion but thank you for the help nevertheless...