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RS232 Control
Remote Connection
The RS232 Interface is designed to control the switch via serial (RS232) daisy chain connection from any host computer or other controller with an RS232 communications port. There is, however, a restriction that must be followed:
A program must be used that will send an entire command line all at once, not character by character. (The HyperTerminal program in WINDOWS cannot be used, as it sends each character one at a time.)
The pin outs for the
RS232 INPUT
PIN | SIGNAL | FUNCTION | |
1 | none | no connection | |
2 | TXD | Transmit Data (RXD at host) | |
3 | RXD | Receive Data (TXD at host) | |
4 | DTR | Data Terminal Ready | |
5 | GND | Signal Ground | |
6 | DSR | Data Set Ready | |
7 | RTS | Request to Send | |
8 | CTS | Clear to Send | |
9 | none | no connection |
On the
Baud Rate
The unit powers up with a default baud rate of 9600 and a fixed data protocol of 8 data bits, no parity and 1 stop bit. The baud rate is selectable through the "Baud Rate Menu". A data protocol of 8 data bits, no parity, and 1 stop bit is used in the daisy chain communication.
Unit Address
To allow multiple units to be controlled from a single host port, the RS232 control interface is designed to allow "daisy chaining" up to 15 units using the NTI
RS232 | |||
Host Serial Port |
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|
CPU |
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|
RS232 |
| RS232 | RS232 |
NTI |
| NTI | NTI |
SWITCH |
| SWITCH | SWITCH |
First Unit | Second Unit | Last Unit |
Figure 3- RS232 Connections for Daisy-chain
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