# 9-Pin Protocol

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Communication protocol

The Sony **9-Pin Protocol** or P1 protocol is a two-way [communications protocol](/source/Communications_protocol) to control video recorders from the beginning of the 1980s onwards. Sony introduced this protocol to control reel-to-reel [type C](/source/Type_C_videotape) [video tape recorders](/source/Video_tape_recorder) (VTR) as well as [videocassette recorders](/source/Videocassette_recorder) (VCR). It uses an [DE-9 D-Sub](/source/D-subminiature) connector with 9 pins (hence the name), where bi-directional communication takes place over a four wire cable according to the [RS-422 standard](/source/RS-422). The used pinout has become a [de facto](/source/De_facto) standard, used by most brands in the broadcast industry.

While nowadays all [post-production](/source/Post-production) editing is done with a [non-linear editing system](/source/Non-linear_editing_system), in those days editing was done [linearly](/source/Linear_editing), using [online editing](/source/Online_editing_(video_production)). Editing machines relied heavily on the 9-Pin Protocol to remotely control automatic players and recorders.

Other protocols appeared that were based on Sony's protocol, such as the [Video Disk Control Protocol](/source/Video_Disk_Control_Protocol) (VDCP) used for [broadcast automation](/source/Broadcast_automation) to [playout](/source/Playout) [broadcast programming](/source/Broadcast_programming) schedules.

From the 2000s onwards, RS-422 was slowly phased out in favor of [Ethernet](/source/Ethernet) for control functions. However its simple way to perform [troubleshooting](/source/Troubleshooting) has delayed its retirement for a long time. Even as of 2025, many modern [hard disk recorders](/source/Hard_disk_recorder) and [solid-state drive](/source/Solid-state_drive) recorders can still emulate a 1982 Sony BVW-75 [Betacam](/source/Betacam) tape recorder. In many cases the devices only support the communications protocol, transported over [Ethernet](/source/Ethernet), but in some cases a 9-pin RS-422 port is also present.

The pinout on the [DE-9 D-Sub](/source/D-subminiature) connector is as follows:

Pin on master on slave 1 Frame ground Frame ground 2 Receive A Transmit A 3 Transmit B Receive B 4 Transmit common Receive common 5 Spare or ground Spare or ground 6 Receive common Transmit common 7 Receive B Transmit B 8 Transmit A Receive A 9 Frame ground Frame ground

## External links

- Sony 9-Pin Remote Protocol (Archived) [\[1\]](https://web.archive.org/web/20150601202908/http://www.belle-nuit.com/archives/9pin.html)

- Copy of Sony 9-Pin Remote Protocol [\[2\]](https://ftp.zx.net.nz/pub/archive/ftp.sgi.com/sgi/video/rld/vidpage/s9pin.html)

- Brainboxes serial port 9-pin protocol support [\[3\]](https://www.brainboxes.com/faq/sony-rs-422-pinout-db9)

- Drastic support of 9-pin protocol [\[4\]](https://www.drastic.tv/support-59/legacysoftwarehardware/37-miscellaneous-legacy/180-vvcr-422-serial-protocol)

- Blackmagic Decklink (a video capture/generation card) support of 9-pin protocol [\[5\]](https://documents.blackmagicdesign.com/UserManuals/DesktopVideoManual.pdf?_v=1657522810000)

- Blackmagic Hyperdeck (an SSD recorder) support of 9-pin communications protocol [\[6\]](https://documents.blackmagicdesign.com/UserManuals/HyperDeckHDManual.pdf?_v=1656918011000)

- Ross Kiva (a presentation server) RS-422 9-pin connector [\[7\]](https://help.rossvideo.com/kiva/Topics/Specs/Server/Ports.html)

- JLCooper [\[8\]](https://www.jlcooper.com/_manuals/legacy/MMC_Converters/MMC-9pin+_User_Manual.pdf)

- Grass Valley K2 Summit (a media server) RS-422 connections [\[9\]](https://wwwapps.grassvalley.com/manuals/k2_summit_v10.0/core/x-cc/content/topic/k2/pinout/r_RS422Pinout.html)

## References

- Protocol of Remote-1 (9-pin) Connector, 2nd Edition, Sony, document number 9-977-544-13

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Adapted from the Wikipedia article [9-Pin Protocol](https://en.wikipedia.org/wiki/9-Pin_Protocol) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/9-Pin_Protocol?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.