There are 2 types of flow control: hardware and software (Xon/Xoff or DC1/DC3). Hardware flow control uses dedicated signal wires such as RTS/CTS or DTR/DSR while software flow control signals by sending DC1 or DC3 control bytes in the normal data wires.

Hardware Flow Control:

List of RF-star BLE Modules Based on Nordic Semiconductor SoC:

• nRF52832: RF-BM-ND04, RF-BM-ND04I, RF-BM-ND08
• nRF52810: RF-BM-ND04C, RF-BM-ND04CI, RF-BM-ND08C
• nRF52805: RF-BM-ND09, RF-BM-ND09A
• nRF52811: RF-BM-ND04A, RF-BM-ND08A
• nRF52833: RF-BM-ND07
• nRF52840: RF-BM-ND05, RF-BM-ND05I, RF-BM-ND06

List of RF-star Modules Based on Silicon Labs SoC:

• EFR32BG22C112: RF-BM-BG22A1
• EFR32BG22C224: RF-BM-BG22A3

Software Flow Control:

RF-star Series Modules:

• RS02A1-A: RSBRS02AA, RSBRS02AI
• RS02A1-B: RSBRS02ABR, RSBRS02ABRI

TI Series Modules:

• CC2640R2FRSM: RF-BM-4044B1, RF-BM-4044B2, RF-BM-4044B4, RF-BM-4044B5
• CC2640R2FRGZ: RF-BM-4077B1
• CC2640R2F-Q1: RF-BM-4077B2
• CC2640R2LRHB: RF-BM-4055B1L
• CC2640R2LRGZ: RF-BM-4077B1L

In order to make sure the normal receiving and transmitting function of the BLE modules, the hardware flow control must care about the CTS pin, while the software flow control must care about BRTS.