The MagPi: Build A Raspberry Pi Telephone Exchange

Earlier this week, The MagPi, the official Raspberry Pi magazine, published a how-to article on creating a wee PBX using a Raspberry Pi, RasPBX and a couple of SIP phones. They invite people to “Transform your humble home phone line into a feature-packed PBX with Raspberry Pi and Asterisk!”

The MagPi Cover 79

I’ve been tinkering with Raspberry Pi for some while. It’s fun little platform. I’m actually awaiting the delivery of an Asus Tinker board so that I can explore the use of such an SBC that’s capable of UHD video output.

It amuses me that this MagPi article appears some 13 years(!) after I wrote How-To: Building an Embedded Asterisk Server for Tim Higgins at Small Net Builder.

Back then, there was nothing like the Pi, so I used a Soekris Net 4801. Being Intel-based, it could run a lightweight Linux-based OS and regular Asterisk distro. I used Astlinux, which was brand new at the time.

Everything old is new again. Except me, of course.

Tip of the hat to WhyADuck for pointing out this article.

Asterisk on Raspberry Pi now has FXO, FXS and GSM Interfaces

The combination of Asterisk and Raspberry Pi harkens back to a time when I was seeking to run Asterisk on an small, embedded platform. I was a little ahead of the curve, seeking this before Digium released AsteriskNOW. I tried Michael Iedema’s Askozia PBX and settled upon Astlinux on a Soekris Net4801, which I used for a couple of years.

Of course, all this was before the now ubiquitous Raspberry Pi was released. It makes sense that someone would try that low-cost SBC as a host for Asterisk. However, there hasn’t been much hardware support for that effort until recently.

oak2_1

Today I read that SwitchPi is now offering modular and multi-port FXO/FXS interfaces, as well as a GSM interface.

  • OAK8X base module (4 onboard Asterisk FXO channels) $130
  • OAK8X base module with 8 channels (8 Asterisk channels, 4 FXO plus 4FXS) $180
  • OAK8X base module with 8 channels (8 Asterisk channels, 8 FXO) $180
  • PiGSM single channel GSM interface $99
  • PiTDM base module $89
  • PiTDM 2 channel FXO module $20
  • PiTDM 1 channel FXS module $10

This is exactly the sort of hardware I tinkered with when I was using Asterisk. I used a TDP400P card with FXS and FXO interfaces. I also used a SIP-to-GSM gateway, documenting the project in the early days of this site.

SwitchPi seems have started in January 2018. It’s good to see hardware support for running Asterisk on Raspberry Pi evolving and affordable.

Sennheiser’s New SDW-5000 DECT Cordless Headsets

A Polycom VVX-600 and Sennheiser DW Pro2 headset are my workaday tools of choice. They have been for years. Polycom VVX remains best-in- class. The DW Pro 2 gives me hands-free flexibility and cordless mobility, sufficient to reach the coffee machine, which is clearly a critical issue.

This pair addressed my quest for practical tools leveraging HDVoice. They explain why I’ve not put much effort into reviews of new desk phones in recent years. The matter has been largely settled hereabouts.

However, they not perfect. There’s room for improvement. In particular, the advent of WebRTC brought a tide of Opus-capable services that would benefit from full-bandwidth audio. The 16 KHz sampling required to support G.722 was great in 2010, but nearly a decade down the road it seems more than a little limiting.

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Unexpected Friends: Pixel & Sennheiser DW Pro 2 Headset

Being in the conferencing business, I’m on the phone a lot during the course of my working life. Most of my phone calling happens via a pair of dear friends; my Polycom VVX-600 and a Sennheiser DW Pro 2 DECT headset. This pair has proven itself in literally years of office use. They’re simply tremendous.

vvx-600 & DW Pro headset

In fact, they’re so good together that my mobile phone was something of an afterthought. I only used it after hours, or when someone called me at that number. That someone was most typically my wife. Stella always calls my mobile. She never calls my desk.

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A little matter of Ego

Quite recently Dave Michels penned a review of the Konftel Ego for the UCStrategies blog. I like Dave. I especially appreciate his no-nonsense approach to things. If he says something is good, it’s probably worth a look.

Konftel’s Ego is a portable, personal speakerphone device with both USB and Bluetooth connectivity. I see that the Ego is listed under $100 on Amazon. Given Dave’s recommendation, and an attractive price, I may need to give it a try. My past experience with the larger Konftel 300 was quite good.konftel-ego-1-vl

That said, I’d also like to take this opportunity to remind you of a very firmly held belief. If you truly care about how you sound to the people at the far-end…if their experience truly matters…you’ll choose a headset over any kind of speakerphone or conference phone. When the quality of experience delivered to the other party is paramount, a good headset trumps all else.

A good headset, preferably one with a boom-mounted microphone, takes the acoustics of the room completely out-of-play. It eliminates any possibility of noise, echo, or reverberance, delivering your message as clear as possible to your audience.

No amount of engineering wizardry can make up for sub-optimal microphone placement. Period.

Conference phones and speaker phones simply cannot deliver a comparable experience. You always trade quality of audience experience for your own convenience.

Yes, a headset…When you care enough to sound your very best.