Bluetooth hex decimal convert to single bytes, help with blocks

Hello, I'm trying to design a simple bluetooth control app that controls a bluetooth relay switch. I can connect to device, but unable to send the hex bytes to control the relay. Anybody offering some code or advice willing to pay for services. Thanks Jeff

What BlueTooth level is this?
BLE or pre-BLE?

There are many BlueTooth examples in the Tutorials section of this board.

Can both be intergrated at same time? the device have now is 1 channel, but need to upgrade to a 4 channel in the future.