BT06 Bluetooth serial port module wireless compatible with HC-06 DIY

SPP-C HC-06 / BT06 HC-06

I purchased 2 sets. One set sold as SPP-Cs and one sold as BT-06s. Both have the same firmware and show up as either BT-04A or ??04-A

When I purchased these I only saw them on taobao and I only saw the HC-06 versions. Now there are HC-05 versions and both the HC-06 and HC-05 are available on the usual sites like ebay and dx.com. The sites I have checked show the same incorrect data sheets as you get from the taobao sellers. Next time I order I may add a couple of the HC-05s to see if there is any difference.

Uses the zs-040 breakout board and has the Bolutek Bluetooth V2.1 version firmware. These are HC-06 slave only modules and the ones I have are 4 pin versions; no STATE pin, no EN pin.

Features the Beken BK3231 chip which is a Bluetooth 3.0 HID device.
Bluetooth v2.1 + EDR
Default baud rate is 9600.
Default PIN is 1234.
Firmware is reported as BOLUTEK Firmware V2.2, Bluetooth V2.1
The firmware is by Bolutek so AT+HELP gets you a list of the available commands.
The modules report themselves as BT04-A or ??04-A

Default to AT mode when powered on. AT commands require line ending characters (\r\n).

If you open the serial monitor and then cycle the power to the module you get