We are a nursing home (a 24/7/365 business) running FreePBX in D&U Mode on a Sangoma 60 box. We have (so far) 4 deskphones (fixed), 3 Android phones (fixed), 6 Android phones (ad hoc) and 13 iPads (ad hoc) - servicing 58 registered Users. D&U Mode works perfectly for us and is now “Business Critical” here. “Floating Users” (in our case nurses and carers but could equally be hotel staff, warehouse staff, factory staff or whatever) grab a “device” (Android or iPad according to their role) from the charging rack at the start of their shift, sign in to it (*11…) and then spend their entire day on the “shop floor”. It has been a revolution in our business - no more “Has anyone seen Claire/Bob/Charlie?” games - a massive saving in man-hours spent simply walking around the 50-plus room premises looking for somebody or disturbing everybody (patients included) with tannoy announcements. This is probably the single most successful efficiency improvement we’ve made in our twenty-year history - more effective inter-staff communication and less wasted time equals better care for our patients.
To emphasise the flexibility afforded us by D&U mode, one of the managers recently left their own smartphone (a second Fixed Device attached to their User record) at home by mistake. No problem - just pick up an Android from the rack and *11 into it with their extension number. This is exactly the kind of flexibility that users expect these days. D&U takes it all in its stride - it’s how a phone system should operate in 2016!
The permutations possible under D&U Mode are apparently without restriction. We can have a mix of Fixed and Adhoc Devices. Adhoc devices can be assigned a Default User (so there’s no need for the Default User to sign in to them), or have no Default User assigned (so they can’t be used for any calls until someone signs in). It’s important to realise that, under D&U Mode, an “Adhoc” Device with a Default User assigned behaves exactly like a regular extension under Extensions Mode - but better, since any other User can Sign In to it and it becomes their extension until Signed Out, at which time it reverts to being the original user’s extension. Basically, if you can think of it, D&U can do it. It means never having to say “sorry, can’t be done” to your users.
After experimenting with every SIP app out there, we now use Media5-fone MPS across all the devices, Android and iOS - it allows central (cloud-based) provisioning which removes much of the headache of administering devices. One important thing we needed was a “company directory” appearing on all the devices - there’s no way users could remember the extension numbers of all their colleagues. We achieved this with a single dedicated Google account which all the devices are logged in to. Contacts entered into that account are picked up by the Media5 app. One day I’d like to implement “presence management” to filter the contacts to only those that are currently signed in, but that’s not trivial. We use a number of ring groups internally - these are also shown in the directory. For example you can ring all the nurses’ mobile devices at once - handy in emergencies. The iPads also run the mobile app which is part of our cloud-based patient management system. The Androids and the iPads are all used extensively as cameras (for recording wound conditions, etc.). A QNAP app runs on all the devices which automatically copies new images to a shared folder on a QNAP NAS in the rack. Thus D&U has allowed us to have each staff member carrying a single device for data, comms and imaging. Priceless. I’m currently evaluating FOP2 to be able to see who’s logged in to the devices at any given time (something FreePBX can’t tell me on its own). And to top it all off, I can monitor and manage the whole setup from my home in Portugal, 1000 miles away from the nursing home in England - ain’t technology wonderful?
As we all know - many modules don’t play nicely with D&U Mode. Strangely, I don’t think anyone has ever compiled a list of which modules have issues. So if you need EPM, Bulk Loader, etc. then you’re bang out of luck. Happily, my business doesn’t need any of those problem modules so it hasn’t been an issue here. I bought EPM, SysAdmin Pro and Extension Routing - EPM works (I believe) if you confine yourself to Fixed or “Adhoc with a (unique) default user assigned”. I can confirm that SysAdmin Pro and Extension Routing work without any issues (that I’ve found). We don’t need/use UCM either. Documentation on D&U Mode is practically non-existent (something I’m planning to help with) but once you’ve got your head around the concept it’s relatively straightforward. And, of course, there’s the support issue - something I’m aware of but willing to carry the risk.
If anyone wants any other info about our setup I’m happy to answer here.
EDIT: just finished playing with FOP2. The answer is “no”. It doesn’t like D&U Mode at all. That leaves me searching for another way to see who’s logged in to the shared devices. A custom Asterisk report might be beyond my capabilities. Actually, the solution will probably be common with presence management for the contacts list, won’t it? thinking…