ask for some Zenbooths and create rule that calls must be taken in them. It makes the open office workable. www.zenbooth.net
(I'm a founder there)
For anyone who doesn't want to drop their email into their webpage to see pricing (yes, I received an outreach email within 15 minutes of doing so) their pricing starts at $4.5k and $14k "on sale". Bit steep for my blood, but, there's obviously some bigger spenders out there!
Unfortunately, team culture takes precedence over neat tools. It's just a common thing on my team to do take calls at your desk.