This interference was caused by RF (Radio Frequency) interference from the phone using GSM technology to communicate with the nearest cellphone tower. It would have been heard by any speaker you were close to. They stopped using this tech after 2g. 3g onward, you no longer heard this anymore.
I had Sony Ericsson Bluetooth headphones (12 years old) that somehow still picked those kinds of signals up.
Used as a party trick of late, as it catches most pings within 10+ meters. And breaks up completely when there are emergency services (police and firefighter squads) nearby.
We gave them to a local hacker club for laughs and giggles.
This interference was caused by RF (Radio Frequency) interference from the phone using GSM technology to communicate with the nearest cellphone tower. It would have been heard by any speaker you were close to. They stopped using this tech after 2g. 3g onward, you no longer heard this anymore.
I had Sony Ericsson Bluetooth headphones (12 years old) that somehow still picked those kinds of signals up.
Used as a party trick of late, as it catches most pings within 10+ meters. And breaks up completely when there are emergency services (police and firefighter squads) nearby.
We gave them to a local hacker club for laughs and giggles.