A. Description of System Interfaces
A.1. Control Port (DB25 Female)
The Control Port is a 25 pin female connector wired in a DCE (modem) configuration.
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Pin | Signal | I/O | Connected | Connected |
2 | RXD | Input | - | To Serial Port Pin 3 |
3 | TXD | Output | Low | Follows Serial Port |
4 | RTS | Input | - | To Serial Port Pin 7 |
5 | CTS | Output | High | * Follows Serial Port |
6 | DSR | Output | High | Always High |
7 | GND | Signal Ground |
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8 | DCD | Output | Low | * Follows Serial Port |
20 | DTR | Input | - | To Serial Port Pin 4 |
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*May be forced high by DIP Switches 9 and 10. Always high when all Serial Ports are connected.
Figure A. 1: Control Port / Serial Port Interface
