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Long Distance Connections
As it is well known usual RS-232 Serial Cables cant be used for long distance connections so what do you do when you want your terminals to be in a distance of 30 meters from your main computer ?
The answer is to use UTP cable and construct serial to RJ-45 adapters. These adapters will be used on your terminal and pc COM port and they will be linked together via the long distance UTP cable.
What you will need:
RJ-45 plugs and UTP cable (you have to buy them and also buy a plug crimping tool)
Serial to RJ-45 Adapters (you have to buy them, then make the connections)
NULL MODEM (you buy it)
RJ-45 plug (UTP) and cable |
DB-9 to RJ-45 Adapter
DB-9 on one side |
RJ-45 on the other end |
Note: These adapters are already contructed by me, you have to make the connections yourself
DB-25 to RJ-45 Adapter
DB-25 on one side |
RJ-45 on the other end |
Note: These adapters are already contructed by me, you have to make the connections yourself
NULL MODEM
|
Used to make the terminal work like in the case of usual RS-232 serial cable |
How to construct the Serial to RJ-45 Adapters
Make the following connections according to the serial port you are using
| DB-9 | DB-25 | Signal | Function | Adapter | RJ-45 |
|---|---|---|---|---|---|
| 8 | 5 | CTS | Clear To Send | Blue | 1 |
| 1 | 8 | DCD | Data Carrier Detect | Orange | 2 |
| 2 | 3 | RD | Received Data | Black | 3 |
| 5 | 7 | SG | Signal Ground | Red | 4 |
| 5 | 7 | SG | Signal Ground | Green | 5 |
| 3 | 2 | TD | Transmitted Data | Yellow | 6 |
| 4 | 20 | DTR | Data Terminal Ready | Brown | 7 |
| 7 | 4 | RTS | Request To Send | White | 8 |
| 6 | 6 | DSR | Data Set Ready | - | - |
| 9 | 22 | RI | Ring Indicator | - | - |
How to make the UTP cable
!!! NOTICE !!!
If you DONT WANT to use a null modem you have to connect the pins of the RJ-45 cable on the one end IN REVERSE of what the pins are in the other side for example what you see above is the one side of the cable with pins being like 1,2,3,4,5,6,7,8, if you dont want to use a null modem the other side shall be exactly the opposite of what you see above (8,7,6,5,4,3,2,1) for example you shall put the brown color which is pin 8 to pin 1 etc etc.
Dumb Terminal Support Center :
How to connect your Linux Box with a serial dumb terminal
How to use your terminal with Microsoft Windows
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