<https://calcuttaelectronics.com/product/hc-06-bluetooth-serial-pass-through-module/#product>
<http://schema.org/description>
"This Bluetooth module can easily achieve serial wireless data transmission. Its operating frequency is among the most popular 2.4GHz ISM frequency band (i.e. Industrial, scientific and medical). It adopts Bluetooth 2.0+EDR standard. In Bluetooth 2.0, signal transmit time of different devices stands at a 0.5 seconds interval so that the workload of bluetooth chip can be reduced substantially and more sleeping time can be saved for bluetooth. This module is set with serial interface, which is easy to use and simplifies the overall design/development cycle."
<https://calcuttaelectronics.com/product/hc-06-bluetooth-serial-pass-through-module/>