RS-422 Device and Controller Hardware

chip rs422Drastic Technologies' VTR and DDR products include the necessary conversion hardware for RS-232 (your computer's serial port) to RS-422 (broadcast VTRs and controllers).  If you are evaluating Drastic DDR software such as MediaNXS, you will need to set up this conversion to test the serial control capabilities of the system. 

Connecting with 232->422 conversion hardware

 
COM1 <- 422 Adapter <- Null Adapter <- 9 pin cable <- External Controller 
COM2 -> 422 Adapter -> 9 pin cable -> VTR
 

Connecting with Drastic's RS-422 Quad PCI-e Card

Installation Instructions

 

Connecting with the Colin Broad Dual RS-422 USB422

 
 

The RS-422 pin out specification (controlling a VTR)

DIN 9 Pin Connector

 

Pin Signal
1 Frame Ground
2 RD A -, Receive A Minus
3 TD B +, Transmit B Plus
4 Transmit Common
5 Spare
6 Receive Common
7 RD B +, Receive B Plus
8 TD A -, Transmit A Minus
9 Frame Ground

RS-422 Control



In this mode the software will control an external VTR or VDCP/Odetics server.  By default COM2: is used for VTR/DDR control.  Converters for this operation are available from:

B&B Electronics Model 422PP9R   (see B&B site for pricing)

Drastic RS-422 NULL                     $59.95 USD

 


Device Emulation (acting as a VTR)

DIN 9 Pin Connector

 

Pin Signal
1 Frame Ground
2 TD A -, Transmit A Minus
3 RD B +, Receive B Plus
4 Receive Common
5 Spare
6 Transmit Common
7 TD B +, Transmit B Plus
8 RD A -, Receive A Minus
9 Frame Ground

RS-422 Emulation


In this mode the software will appear as a VTR or VDCP/Odetics server.
By default COM1: is used for VTR/DDR emulation.  Currently there are no commercial converters with this exact wiring.  Fortunately, standard converters (as above) can be rewired to the correct wiring for device emulation.  Drastic is also developing  a solution to this problem.

B&B Electronics Model 422PP9R   (see B&B site for pricing)

Drastic RS-422 NULL                     $59.95 USD

 


RS-422 NULL Cable

Currently a pin converting cable is required to use device control converters as device emulator converters.  This cable will only work with a 'fully wired' RS232-422 converter such as the B&B above.  Many low cost converters only include a single 422 balancing circuit.  This works fine for VTR control as the VTR sees the balanced serial properly, but with the NULL cable, the device no longer sees the balanced signal.

 

RS422C Pin

Purpose

RS422D Pin

1 Frame Ground 1
2 RD A -, Receive A Minus 8
3 TD B +, Transmit B Plus 7
4 Transmit Common 6
5 No Connect 5
6 Receive Common 4
7 RD B +, Receive B Plus 3
8 TD A -, Transmit A Minus 2
9 Frame Ground 9

RS-422 Null Wiring

 


Hardware Solutions

There are a number of RS-422 PCI and ISA cards that may be used in place of the on-board COM ports.  Once installed, the software can be configured to use the ports using the setup program supplied in the installation.  With the cards, the wiring setup is critical.  Please refer to the diagrams above for the correct wiring for each mode.

Comtrol