"Morse code" like sound on phones?
 

Don't know how to describe it, but it is a recent phenomenon.

duh-duh-duh, duh-duh-duh, duh-duh-duh. Fairly fast paced, a few iterations and it's gone. perhaps around ~200Hz, but multi-frequency, not a pure tone.

My associates speakerphone does it - even when not being used for a call. Her theory is that a nearby cellphone is receiving a call and her desk phone is reacting to the signaling. This doesn't seem likely to me.

I heard it a lot on a conference call today and someone remarked that it was an artifact of VOIP. That sounds more plausible.

Anyone know what I mean, or shall I try to record it sometime?

That's GSM signalling. CDMA doesn't do that but IS-136 (old AT&T/Cingular 'Digital') does. Very good ear, it's a 217 Hz signal which is the frame repetition rate. IS-136 is 50Hz. So if you hear that noise, look around for someone with a T-mobile/Cingular device. It's them sending a text/getting a text/using data, etc.

Thank you kanebear. Once more you impress me with your knowledge. :eek:

I have a Cingular RAZR and shall try this out forthwith. It's odd that it couples so well onto a wired voice system.

I used to wear hearing aids which suffered from mobile phone interference from GSM phones.

I always got distinctive noises just *before* Mr Falconea's phone rang.

Other people thought it was magic when I'd tell them, "your phone's about to ring!".

Sort of sadly, the new modern aids don't do the same thing.

Audrey

It also is endemic with Nextel phones with the two way paging capabilities. If you really want to make a meeting really interesting, put your phone/pager right next to the microphone on the conference table. The non-shielded type will make the sound system go crazy! I purposely design my systems to overcome this weakness!

Unless I'm mistaken a GSM phone will also cause this interference as it periodically renews its connection to the tower, whether it's in use or not. My T-mobile phone used to excite my answering machine like that from time to time even if I wasn't getting a call or anything.

Sometimes it comes out of the phone jack in my bedroom. There's not even a phone plugged into it. :eek:

Hear it on Bose NR headsets.

Not sure about GSM (no Cingular GSM in this area), but Cingular digital phones do this as well. When my phone (a Nokia 6030) is anywhere near computer speakers or an FM radio it causes the above descrbed interference. I get this interference a lot in my car as well.

On a related note, my company (one of the large package delivery companies) uses hand-held computers which communicate via cell technology. I can always tell when a unit is transmitting because I can hear that telltale "morse code" coming through the delivery truck's comm radio.

I assume you have the wrong model number in there, because a Nokia 6030 is a dual-band (900/1800MHz) GSM phone that won't work in the US. Either that, or Nokia marketing is re-using model numbers :(

That's exactly what it is. If I had to describe it, it'd be a...

bap-a-dap-bap-a-dap-bap-a-dap-bap-a-dap

and when the mobile terminal is answered you get the above and then

baaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aa

(as the voice signal is constant and has no breaks when the mobile party is talking, so you get a constant 217 Hz tone). Not sure if anyone listens to Opie and Anthony (shock-jock radio on XM), but almost daily you'll hear someone's phone doing this.

Cingular/AT&T TDMA will do the same thing but it's at a much lower frequency (50Hz) and is a low buzzzzzzzzzzzzzzzz.

Nextel's frame repetition rate is 17Hz so you never hear a buzz, it's more of a series of 'pfffst' sounds.

Bluetooth interference?
 

I thought it was Bluetooth interference. Whenever I'm on my desk phone, I'll get that same sound just before my cell phone rings.
My Bluetooth is always on and I thought it was trying to signal the headset and causing interference on deskphone.

When the wi-fi at a residence of mine drops it's the prequel to the VOIP lines ringing (on the cordless phone system). The game is, "there's an incoming call [snap fingers] "now".

Didn't have much time yesterday, but I went into my associates office and texted myself. Sure enough, her phone made the sound. I think her phone reacts that way, and not the other phones, it because it is the only one with a wireless headset.

I've noticed that some speakers - particularly cheap, unshielded PC speakers are very vulnerable to this. I've had clients complain that their speakers must be going bad due to this noise. Of course, they have their cell phones sitting on the desk not 6 inches from the speakers. Showing them what causes it and seeing the understanding flash across their faces is sometimes priceless.