I know it's two years after you asked the question, but I wanted to answer this for anyone else who comes across this, because I had the same question, and I believe I found the answer is here: https://www.cisco.com/c/en/us/td/docs/routers/xr12000/so...

Christopher,    I'm sorry to tell you, but the older WIC-1DSU-T1 card is not supported in the 2811.  You'll need to get the WIC-1DSU-T1-V2 card.A full list of WICs and modules for the 2800 series routers is available at:http://www.cisco.com/en/US/pro...

Alex,    That's a fascinating issue.  I didn't know audio equipment came with x.21 and ethernet these days.  Can I ask what particular audio codec you are working with?      I think that as long as you can get the codec to send data into the cisco ro...

Jake,    I'm not an expert with the ASA, but earlier this year I was troubleshooting performance on our ASA, and found this helpful document:http://www.cisco.com/en/US/products/ps6120/products_tech_note09186a0080ba9521.shtmlWe found a duplex mismatch...