Problem with S705 and Motorola CB

[riwer (Bosnia & Herzegovina)]

So I have a strange problem with Sangoma phone and Motorola CB, my organization uses CBs (security guards) and when they are on the phone and need to talk over CB when they push talk button (on CB) phone automatically puts active call on hold
Is this some random thing or is there an option to turn it off
(BT and WiFi are not used and are off)

[david55]

If by CB you are referring to 27MHz, relatively high power (up to 4W in the UK) walkie talkies, they will put significant strain on EMC (electromagnetic compatibility) capabilities of any electronics close to them.

Depending on the size of the site, and assuming European type standards, PMR446 (500mW), or PMR 433 (10mW), might cause less problems.

For comparison, WiFi is 100mW.

Mobile phones can be up to 3W, but will reduce power if there is a good connection to the cell tower, and are at a much higher frequency. It is much more likely that consumer electronics is designed to cope with very close by mobile phones, although, even then, GSM phones had the ability to upset audio equipment.

[david55]

It would appear this issue has arisen before, and there was a solution, but it would, I assume, void the warranty:

Sangoma S70x phones and Walkie Talkie Interference

I’ve got a client we deployed a couple dozen S705’s. The client is a warehouse with most of the phones in their office portion, and a few in the warehouse. They heavily use walkie talkies to communicate. I’ve observed their radios frequently interfere with the Sangoma Phones and cause all kinds of strange behavior. It frequently causes false button presses, like placing calls on hold, or enabling DND among other unwanted behavior. I’m 100% certain the radios are the cause. Phones are powered b…

In that case, the device causing the interference had a power of 1W, and operated on UHF, not CB, frequencies, although I wonder if CB really means CB, here. It was Motorola.

Sangoma do claim EN 55024:2010 compliance, but that is behind a pay wall, and I don’t know what it assumes in terms of medium power transmitters almost on top of it.

[bmartindcs (Brian Martin)]

I’m OP of the referenced issue. Indeed the issue this OP is talking about is exactly the same thing I had. My solution does work, and does void the warranty however these phones never break during the warranty so that is moot.

The first phone you do takes a bit longer, but once you get going the rest take about 15 min each. I had one of my guys go around doing all of them at this client and had them finished in 1 day. Just spray the plastic housing with the EMF shielding spray (I’m thinking any metallic spray would work probably) and re-assemble. Just make sure to mask the edges/glass bits and remove the button/moving-parts.

Can’t believe this is STILL an issue. I reported this to Sangoma long ago. It would cost pennies to fix during manufacturing if they sprayed them then.

[riwer (Bosnia & Herzegovina)]

Thanks for the info

I can see you had an interesting journey tracking this problem down