The 9-Pin Protocol is a two-way communications protocol

Communications protocol

A communications protocol is a system of digital message formats and rules for exchanging those messages in or between computing systems and in telecommunications...

 for the RS-422 D-sub electrical connector

Electrical connector

An electrical connector is an electro-mechanical device for joining electrical circuits as an interface using a mechanical assembly. The connection may be temporary, as for portable equipment, require a tool for assembly and removal, or serve as a permanent electrical joint between two wires or...

 interface, in which a bi-direction signal is transmitted over a single, four wire, serial cable

Serial cable

A serial cable is a cable that can be used to transfer information between two devices using serial communication. The form of connectors depends on the particular PHY used...

 to allow the remote control of a wide variety of devices including, reel-to-reel type C videotape video tape recorder

Video tape recorder

A video tape recorder is a tape recorder that can record video material, usually on a magnetic tape. VTRs originated as individual tape reels, serving as a replacement for motion picture film stock and making recording for television applications cheaper and quicker. An improved form included the...

s (VTR) as well as videocassette recorder

Videocassette recorder

The videocassette recorder , is a type of electro-mechanical device that uses removable videocassettes that contain magnetic tape for recording analog audio and analog video from broadcast television so that the images and sound can be played back at a more convenient time...

s (VCR).

The online editing

Online editing

Online editing is an older post-production linear video editing process that is performed in the final stage of a video production. It occurs after offline editing...

 control units used in post-production

Post-production

Post-production is part of filmmaking and the video production process. It occurs in the making of motion pictures, television programs, radio programs, advertising, audio recordings, photography, and digital art...

 relies heavily on the 9-Pin Protocol to remotely control auotmated linear editing devices that use sequential access

Sequential access

In computer science, sequential access means that a group of elements is accessed in a predetermined, ordered sequence. Sequential access is sometimes the only way of accessing the data, for example if it is on a tape...

 methods.

In broadcast automation

Broadcast automation

Broadcast automation incorporates the use of broadcast programming technology to automate broadcasting operations. Used either at a broadcast network, radio station or a television station, it can run a facility in the absence of a human operator...

 the Video Disk Control Protocol

Video Disk Control Protocol

Video Disk Control Protocol is a proprietary communications protocol primarily used in broadcast automation to control hard disk video servers for broadcast television. VDCP was originally developed by Louth Automation and is commonly called the Louth Protocol...

 (VDCP) use the 9-Pin Protocol to playout

Playout

In broadcasting, playout is a term for the transmission of radio or TV channels from the broadcaster into broadcast networks that delivers the content to the audience...

 broadcast programming schedules.