The Sony 9-Pin Protocol is a 2-way communications protocol for controlling advanced video recorders. Sony introduced the protocol to control reel-to-reel Type C Video Tape Recorders (VTR) and VideoCassette Recorders (VCR). It uses a DB-9 connector with 9 pins, where bidirectional communication takes places over a four wire cable, with accordance to the RS422 Standard.

In the Sony RS422 Protocol, the Controller/Master is defined as the equipment which controls a VTR and the Device/Slave is defined as the equipment which is being controlled. If connecting to a Brainboxes DB9 serial module, it’s important to verify whether your Brainboxes module is a Controller or a Device as the physical wiring configuration will change depending on this.

Below are the pinouts of the Sony RS422 protocol, using a DB9 serial connector:

Sony RS422 Controller (Master)	Sony RS422 Device (Slave)
Pin Direction Name Description 1 — GND Frame Ground 2 —> RX_A Receive A- 3 <— TX-B Transmit B- 4 — TX-GND Transmit Ground 5 — N/C Not Connected 6 — RX-GND Receive Ground 7 —> RX-B Receive B+ 8 <— TX-A Transmit A+ 9 — N/C Not Connected	Pin Direction Name Description 1 — GND Frame Ground 2 <— TX-A Transmit A- 3 —> RX-B Receive B+ 4 — RX-GND Receive Ground 5 NC Not Connected 6 — TX-GND Transmit Ground 7 <— TX-B Transmit B+ 8 —> RX_A Receive A- 9 NC Not Connected

Below are 2 examples of using a Brainboxes ES-320 Ethernet to Serial module with a Sony DB9 VTR. The first example is where the ES-320 is being used as a Controller, with the second using the ES-320 as a Device:

ES-320 Master

ES-320 Slave