Making Use of Wideband Voice Right Now!: OnSIP
You will find references to Junction Networks’ OnSIP hosted IP-PBX service scattered all over this site. I’ve use them since the summer of 2007 for my home office phones. They’re extremely reliable, 100% SIP based and even wideband capable in many respects.
The basics of the OnSIP service are pretty simple. If you are a company and need the usual services you establish an OnSIP account, selecting one of their monthly service bundles. These run from $39.95/mo to $199.95/mo, scaling up to suit companies of various sizes. They offer a 30 day free trial to let you get your feet wet.
Pixel Power, my employer these past ten years, uses Microsoft Dynamics CRM. We don’t love it, but we need it and we really do use it. It’s taken a long time to get it worked into our corporate culture. We started with v2.0 and have since migrated to v3.0, with a further step to v4.0 coming in the next couple of months.

