4 ms·

Ha! I think I think I know why ⌕ is the symbol for “telephone recorder”. It’s because of products like this: https://www.summitsource.com/Eagle-Telephone-Pick

Ha! I think I think I know why ⌕ is the symbol for “telephone recorder”. It’s because of products like this: https://www.summitsource.com/Eagle-Telephone-Pick-Up-Coil-with-Microphone-with-Suction-Cup-to-Record-Phone-Conversation-on-Any-Tape-Recorder-with-35mm-Input-Amplify-Phone-Calls-P11741.aspx https://www.summitsource.com/Eagle-Telephone-Pick-Up-Coil-wi... Instead of having a device sitting on the phone line, this just suctions on to the handset, and uses a microphone to pick up the sound vibrations. Similar to how a Jawbone headset works when clipped to your head!

edent 7y ago
Oh! That's interesting. Thanks!
Someone 7y ago
”this […] uses a microphone to pick up the sound vibration” It’s described as a ”Telephone Pick Up Coil with Microphone”, but I don’t see how one would need both a coil and a microphone to pick up the signal, and I would think a coil to be the more reliable method, so I suspect it only has a coil, picking up the signal though electromagnetic induction (https://en.wikipedia.org/wiki/Electromagnetic_induction https://en.wikipedia.org/wiki/Electromagnetic_induction)
- pwg 7y ago
  It likely has both. Coil: to pickup via electromagnetic induction the voice sounds of the remote speaker. Microphone: to pickup the voice sounds of the local speaker (the person holding the handset to which this device would be attached). You likely would stick the device to the end of the handset with the speaker, where the coil could pickup the relatively strong electromagnetic signals from the speaker mechanism within the handset. But as that end would put it about six inches away from the microphone portion of the handset, leaving little electromagnetic induction possibility available, the 'microphone' part would then be present to pickup the speaker directly.
  - kayfox 7y ago
    Its just an inductive pickup. In most phones some of your voice is fed back into the earpiece, this is called sidetone and is used to make you self regulate the volume of your voice. https://en.wikipedia.org/wiki/Sidetone https://en.wikipedia.org/wiki/Sidetone

edent 7y ago

Oh! That's interesting. Thanks!

Someone 7y ago

”this […] uses a microphone to pick up the sound vibration” It’s described as a ”Telephone Pick Up Coil with Microphone”, but I don’t see how one would need both a coil and a microphone to pick up the signal, and I would think a coil to be the more reliable method, so I suspect it only has a coil, picking up the signal though electromagnetic induction (https://en.wikipedia.org/wiki/Electromagnetic_induction https://en.wikipedia.org/wiki/Electromagnetic_induction)

pwg 7y ago
It likely has both. Coil: to pickup via electromagnetic induction the voice sounds of the remote speaker. Microphone: to pickup the voice sounds of the local speaker (the person holding the handset to which this device would be attached). You likely would stick the device to the end of the handset with the speaker, where the coil could pickup the relatively strong electromagnetic signals from the speaker mechanism within the handset. But as that end would put it about six inches away from the microphone portion of the handset, leaving little electromagnetic induction possibility available, the 'microphone' part would then be present to pickup the speaker directly.
- kayfox 7y ago
  Its just an inductive pickup. In most phones some of your voice is fed back into the earpiece, this is called sidetone and is used to make you self regulate the volume of your voice. https://en.wikipedia.org/wiki/Sidetone https://en.wikipedia.org/wiki/Sidetone