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 |

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 |
|