Public Address (Paging) Options for Microsoft Teams – I

It’s been over 6 years years since I published two how-to guides on ways to interface your (then) on-premises Lync deployment to a public address / paging system:

Given the Cloud-based architecture of Office 365 and Microsoft Teams I thought I should revisit the subject, see if they’re still relevant, and if there are any superior ways of doing same.

I’m pleased to say that both remain relevant in a cloud-based deployment, although they require a CCE or Microsoft Teams Direct Routing (DR) SBC in order to add the required FXO port or SIP connectivity.

OK, so that’s not everyone these days. What alternatives do we have?

A VVX Paging Interface

If you’re using Microsoft Teams without DR, or SfB with Microsoft’s Phone System you won’t be able to use the interfaces described in those previous posts, but thankfully there’s a way to do this using a Polycom VVX. The trick is the combination of a cable that will join the phone and the PA, and a special config file that enables the phone’s “auto-answer” feature.

Here’s the test rig I used in my Lab – a VVX410 with the referenced cable adapter, plugged into a cheap set of USB speakers, simulating the PA system. If you only want to broadcast to a room (workshop, lunchroom etc?) then just substitute a more grunty set of USB speakers and you’re done!

VVX-PAInterface

Add some access control

One of the dangers of hooking a phone to your PA system is that anyone can just call the phone. Needless to say, this gets MIGHTY risky if you’ve deliberately or otherwise given the phone a number in your indial range. THAT’S not something you’re going to want a malicious ex-employee knowing!

The primary ways to shield it from external access are to EV-disable the account / leave it without a Phone System licence / don’t assign a LineURI.

Adding some security through obscurity is always a good idea too, so if you can, hide the account from the Address Book.

To lock the account down so only authorised parties can initiate a page, you need to leave the phone permanently in Do Not Disturb. Here’s how-to, depending on your platform:

SfB

  • sign into the PA account from an SfB client – my app bounSky is great for this – and tweak that user’s config
  • add the people authorised to initiate a paging call to its contact list, then change their Privacy Relationship to “Workgroup”
  • click Tools / Options / Alerts and set “When my status is Do Not Disturb” to the middle “Show only conversation alerts …” selection
  • finally, set the account to Do Not Disturb. (Yes, when you’re in DND your Workgroup are still able to call you)
  • don’t forget to sign out of the PA account!

Microsoft Teams

  • sign into the PA account from the Teams client
  • click the picture (or the initials) in the top right, then Settings
  • On the Privacy tab, click “Manage Priority Access”
  • Add the people authorised to initiate a paging call, then exit Settings
  • finally, set the account to Do Not Disturb
  • don’t forget to sign out of the PA account!

Unfortunately Microsoft Teams isn’t honouring DND here at the moment. I don’t know if that’s a bug or a problem due to the phone being signed-in through the SfB gateway (the VVX not being a native Microsoft Teams device). I also see there are several UserVoice requests around issues with DND, so I suspect it’s still being worked on.

I’ll update here when/if that changes, and if anyone can shed any light on this, please leave a comment below.

Notes

  • Make sure you plug the adapter into the handset port
  • The Admin guide says auto-answer won’t work on all models:
    This parameter cannot be used with VVX 101, 150, or 201 phones
  • Should the phone restart at any time, the “Tweedle-Ip” reboot tune plays through the phone’s speaker, not the headset/PA output. (Phew!)
  • The phone automatically signs back in after a reboot
  • For the phone to auto-answer you need to leave the handset out of the cradle and the switch-hook up. On my 400 and 500 I found I could slide the wall-mount cradle clip “thingy” up, wedge a gob of Blu Tak or similar to stop it sliding back down, and it nicely obstructs the switch-hook. Alternatively – if you’re careful – a small self-tapper screw into the case can achieve the same result:VVX-BluTakSwitchHook
  • I found in my mock-up with the dodgy speakers I had some earth hum (buzz) in them that wouldn’t be acceptable in production. Swapping to a higher-powered USB power supply reduced it significantly. If you’re still plagued by noise, consider an isolating transformer and/or add a ground on the audio side.

Shopping List

Amazon sold me a 2-pack of the “Onvian RJ9 Male to 2 3.5mm Female Headset Phone MIC Audio Splitter Adapter Cable” for a lousy $USD10.

Amazon-OnvianSplitterAdapterCable

Download

The VVX config file referenced in this article is in my master VVX repo at GitHub.

This contains a few tweaks to my usual config, some of which are:

  • Auto-answer is on (natch), with the mike muted.
  • I’ve tweaked PowerSaving, trying to keep the screen awake, although that’s (so far) proven impossible. The goal is to permanently display a warning wallpaper like this, and you can get the dimensions from this post:

    VVXScreenShot-PAInterface

  • *ALL* of the buttons on the phone EXCEPT vol up/down are disabled. I thought they were the only ones that can remain enabled, as they allow fine-tuning of the audio from the phone itself. (Note that my configs have always had “voice.volume.persist.handset” set, so the level won’t change between calls).

Credits / Reference

  • Matt Landis and I both saw the same product referenced on Twitter (thank you @KevinKrautle) and were spurred into action.
  • Matt’s post on the subject is here. He beat me to the punch by 12 months.
  • I use James Cussen’s “VVX Manager” script for the effortless captures of the phone’s screen.
  • Credit to Jersey down in Canberra for the button-disabling config, previously referenced in my courtesy phone config.
  • Thanks as always to Rocky for the photos. Trivia: the lead photo needed to be taken after dark with strobes for illumination + a 2s exposure time to capture the screen.

Revision History

19th January 2019. This is the initial post.

– G.

2 Comments

    • Hi Marcus.

      Registering a VVX to Teams is the same process as registering it to SfB Online. The trick is to make sure you use the web signin process – and your VVX config might have that disabled if it’s been configured for an on-prem environment.

      – G.

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