You did not state what exact model of Rexton you want to connect?
Is it Rexton BiCore or Rexton Reach ?
Soundsync BA200 Bluetooth Transmitter/Receiver seems to support Bluetooth Classic and APTX only.
The Rexton hearing aids can NOT connect to this BT-Transmitter.
The Rexton (Signia) hearing aids support Bluetooth via ASHA and MFi only to connect to dedicated smartphones.
on the market there are no free Bluetooth Transmitters available that allow a direct connection to MFi / ASHA hearing aids.
You only can get the available intermeditary device Rexton Smart Mic to connect your hearing aids to any Bluetooth classic source. The Smart Mic can connect to the BA200 Bluetooth Transmitter, and the Rexton hearing aids connect via Smart Mic.
Find info under ACCESSORIES section: How to use Smart Mic, Smart Transmitter
If you have the latest/newest Rexton Reach with **Bluetooth LE Audio (BLEA) ** , then you can use FlooGoo FMA120 Bluetooth dongle for connect to a PC and other devices (TV) that support audio-out over USB.
For more Infor about FlooGoo FMA120 dongle see here: