I am looking for a bluetooth adaptor that I can plug into the landline phone in my office, or rather the receiver cord, and that will allow me to make calls from the landline phone using a Bluetooth headset.
Something like https://www.amazon.com/Hqtelecom-Bluetooth-Telephone-Landline-Headset/dp/B00A0X9X00 except maybe not as expensive and definitely home-made.
Is there a way to make an Arduino with a Bluetooth shield pretend that it is a phone receiver so that I can connect it to a landline phone in place of its normal receiver using a standard RJ9 plug?