I'm a PM, and I consider it my most important responsibility to prevent interruptions from reaching developers. By redirecting inwards-bound interruptions to myself, I've probably reduced developer interruptions by 80% since I started.
What I've found is that the typical developer/engineer is really bad at saying "no" or "not now" to others. The solution then is to work the other side (sales, marketing, etc) to interrupt someone else (me) instead. Even if it's a relatively simple technical question from sales, I can convert the in-person active interruption to a passive email notice (at the very least).
The typical office environment (and system) is not productive, so at this point it's up to the individuals to reduce the impact of the system on the team's productivity. (which is a sad reality...)
What I've found is that the typical developer/engineer is really bad at saying "no" or "not now" to others. The solution then is to work the other side (sales, marketing, etc) to interrupt someone else (me) instead. Even if it's a relatively simple technical question from sales, I can convert the in-person active interruption to a passive email notice (at the very least).
The typical office environment (and system) is not productive, so at this point it's up to the individuals to reduce the impact of the system on the team's productivity. (which is a sad reality...)