Back-to-Back Connections to a Second Modem
Rx | Rx |
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Rx | Rx |
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Tx | Tx |
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Tx | Tx |
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Modem 1 | Modem 2 |
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RS-232 (RTU) Interface
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Signal | Modem | DB25 | Description |
Name | Input/Output | Pin |
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Earth GND | | 1 | Earth Ground |
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TXD | Input | 2 | Transmit Data |
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RXD | Output | 3 | Receive Data |
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RTS | Input | 4 | Request To Send |
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CTS | Output | 5 | Clear To Send |
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DSR | Output | 6 | Data Set Ready |
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| (Modem Ready) |
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SG | - | 7 | Signal Ground |
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DCD | Output | 8 | Data Carrier Detected |
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DTR | Input | 20 | Data Terminal Ready |
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| (Host Ready) |
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Page 33
