The 350's workgroup bridges are not designed to the use you want to give.
You should use the 350 wireless bridges for your point-to-point wireless link. For a 17Km link, the parabolic dish works very well. You also have QoS and other options, since you're going to pass VoIP.
I had a client who uses a wireless network to pass VoIP and normal IP traffic, it works very well.
Thanks for your reply. When talking with some Cisco guy from pre-sales, he told me that I can make the link using one Bridge and one Workgroup Bridge. What do you think about? He'll borrow me one and one to make a test.
Just a couple of things to be aware of. On a Wireless link over 6 miles (which this is) it will be affected by "Earth Bulge", that is, line of sight, essential in this type of connection, will be lost. I take it that you either have antenna masts or your buildings are of a reasonable height, upon which you can place the parabolic dish, mentioned in a previous post.
Also, just to confirm, the Workgroup Bridge is designed for connecting up to 8 PCs that cannot support wireless equipment themselves to a Wireless AP. I have never heard them being used for this type of implementation. You would certainly lead a couple of bridges for this. However, if you get the WGB to work, let us know!