The TC66C is a USB-C load meter that communicates its measurements over Bluetooth Low Energy.
TC66C units that come with firmware version 1.15 preinstalled appear to contain new/different Bluetooth hardware.
They use a different set of characteristics:
- primary (transmit & receive):
0000ffe0-0000-1000-8000-00805f9b34fb - txChr:
0000ffe2-0000-1000-8000-00805f9b34fb - rxChr:
0000ffe1-0000-1000-8000-00805f9b34fb
Furthermore, the txChr doesn't allow a reliable-write. Instead (and perhaps
more sensibly) it expects a command-write ("write without response" – see
https://github.com/bluez/bluez/blob/master/doc/gatt-api.txt).
Issuing a reliable-write causes a ERROR: DBusError: Write not permitted to
be raised. To be able to issue a command-write, at least
node-ble 1.5.0 is required.
N.B. the older units require a reliable-write to function properly (they
will not issue an error when send a command-write, but won't produce any data
as a result either).
Apart from the above two changes, all other aspects (including the AES decryption-key) remain unchanged.