According to the memo on my bulletin board, as of March 31, 2011 Siemens has end of life'd all of the "legacy" products, including 9006 and Phonemail, and will no longer provide custom MAC (which means everything is limited to stock on hand from your support organization or the 3rd party channel). I thought PhoneMail did a great job, and yes, it was very easy to work with. I actually still have my single node Phonemail 6.4 with two drives sitting in the phone room keeping someone from stealing my real estate.
Yes, I have planned to stay with Siemens for the VOIP rollout, for a couple of reasons which really piss off the barrage of vendors that keep hassling me. One of the reasons is that we have already rolled out the 4000 V5 at one site and it has been running for 3 years with no problems. We already know it works for us and is reliable, and I already have about 30 IP phones rolled out in various remote locations off of it. Because we are a healthcare organization with the main hospital and 7 sites and about 1200 devices it would be a tremendous hassle to try to do them all in one weekend. The nice thing about staying with Siemens is that the networking protocol between sites does not have to change initially, which means I can drop in each remote site without anyone else in the network really knowing it's happening. We build the system, set the IP phones, swing the PRI from the old system to the new, and the CorNet trunk, and we're cut over. Then we go back and pick up the old stations and remove the old system. Eventually when they're all up we change to IP for the inter-facility links and either re-task the DS1s as more bandwidth or just eliminate them completely. The only significant outage will be at the hospital, and only then because it will take a while to swing the 3 primes and 7 DS1s, plus move the voicemail and RightFax over to the new box. That is the most seamless upgrade path I could have imagined. Another reason is that I want to run a hybrid system because of the hospital. I want the redundancy of TDM phones alongside the IP phones in critical locations, so in the event something happens to the network or we have a facility power failure I can sustain basic communications and paging. This solution will also play very well into that. We will take the existing "brain" I already own and upgrade it to V6, then move it to the main hospital. Each individual remote site will be survivable and will retain its own trunking in the event it loses communication with the mother ship. That also allows me to minimize the IP network traffic that would happen from routing all the external traffic for the remote sites across the network, and if I have a PRI failure at any of the remote sites I will be able to do backup dialing from the mother ship or one of the other remote sites, and I can also use CLAR (AT&T thing) to move that site's traffic to a different PRI and then route it across the network until the outage is repaired.
I've spent a lot of time trying to develop a system that will give us the most flexibility and redundancy, and also minimize the disruption to the organization when we roll it out. I guess we will find out! I am planning on making the vendor "haul away" all of the old stuff that I can't re-task as part of the deal to save me the disposal and hauling costs. They have a resale operation so I'm sure it will have at least some value to them to recover their costs.