FAQs

 

Q1 What is the pin-out for an RS422 connector
Q2 What are the signal levels on an RS422 line
Q3 How should the cable be wired to the connector
Q4 How do I interface RS422 signals to the PC RS232 port
Q5 Which programming languages were used in the products
Q6 Do any of the programs have an API for external access
Q7 Are the programs checked for viruses

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Q1 What is the pin-out for an RS422 connector
A1 A 9-pin D connector is used for RS422 VTR remote control:-
1 Ground 6 Device Gnd
2 Device Tx- 7 Device Tx+
3 Controller Tx+ 8 Controller Tx-
4 Controller Gnd 9 Ground
5 Spare

All VTRs and controllers have 9-pin sockets, interconnecting cables have plugs at both ends and are wired pin to pin without any crossovers

 

Q2 What are the signal levels on an RS422 line
A2 The RS422 standard uses two pairs of wires - one pair to transmit data and one to receive data.
One wire in a pair carries a non-inverted signal (Tx+ & Rx+) which idles at +5v, and the other wire an inverted signal (Tx- & Rx-) which idles at 0v.

 

Q3 How should the cable be wired to the connector
A3 Ideally the cable should contain two individually screened twisted pairs and an overall screen, in which case:-
1 Overall screen 6 Pair 1 screen
2 Pair 1 wire A 7 Pair 1 wire B
3 Pair 2 wire B 8 Pair 2 wire A
4 Pair 2 Screen 9 Overall screen
5 Spare

 

Q4 How do I interface RS422 signals to the PC RS232 port
A4 PCs come equipped with one or more RS232 ports, these are not directly compatible with the RS422 signals used in VTR control. There are two solutions to this problem - either use an external inline convertor unit or fit an RS422 interface card to the computer.
If selecting inline convertors check with the supplier that the 9-pin connectors are wired correctly for VTR use and the unit is capable of driving terminated lines.
Internal interface cards generally have a multipole connector that will need an adaptor lead to convert to the 9-pin VTR standard.

See 232422b.zip for schematic of simple RS232/422 interface

 

Q5 Which programming languages were used in the products
A5 VTRemote - 80286 assembler, Borland Pascal 7, Borland Turbo Vision
VTMultiQ, ParRes - Delphi 1 (16 bit)
Remaining programs - Delphi 6 (32 bit)

 

Q6 Do any of the programs have an API for external access
A6 The only programs providing these facilities are DeckCtrl and DeckSim all other programs are self contained

 

Q7 Are the programs checked for viruses
A7 Yes - using the latest version of McAfee Anti Virus suite

 

 

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Last modified: June 29, 2013