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Appendix F - Pin Descriptions
Appendix F - Pin Descriptions
RS-232 Pin Descriptions
Label | Pin | I/O type | Signal name/description |
CGND | 1 | GND | CGND is tied common to GND on the modem’s PCB. |
TD | 2 |
| Transmitted Data The DTE uses the TD line to send |
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| data to the modem for transmission over the telephone |
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| line or to transmit commands to the modem. |
RD | 3 |
| Received Data The modem uses the RD line to send |
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| data received from the telephone line to the DTE and to |
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| send modem responses to the DTE. |
RTS | 4 |
| Request to Send The RTS signal is used for hardware |
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| flow control. |
CTS | 5 |
| Clear To Send CTS is controlled by the modem to indi- |
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| cate whether or not the modem is ready to transmit data. |
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| CTS high indicates to the DTE that signals presented on |
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| TD will be transmitted to the telephone line. CTS low in- |
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| dicates to the DTE that it should not transfer data across |
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| the interface on TD. |
DSR | 6 | Out | Data Set Ready DSR indicates modem status to the |
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| DTE. DSR low indicates that the DTE is to disregard all |
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| signals appearing on the interchange circuits except |
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| Ring Indicator (RI). It reflects the status of the local data |
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| set, and does not indicate an actual link with any remote |
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| data equipment. |
GND | 7 | GND | Ground. |
CFLO | 8 | CD | Carrier Detect The modem uses the CD line to signal |
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| to the DTE that a carrier has been detected. |
+12V | 9 |
| A positive voltage output from the modem used for tests |
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| or for strapping signals high if needed. |
| 10 |
| NC |
| 11 |
| NC |
| 12 |
| NC |
| 13 |
| NC |
| 14 |
| NC |
TCLK | 15 | TC | Transmit Clock Output from modem, used in syn- |
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| chronous mode. |
| 16 |
| NC |
RCLK | 17 | RC | Receive Clock Output from modem, used in synchro- |
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| nous mode. |
18 | AL | Analog Loop Input to modem to enable analog loop test. | |
| 19 |
| NC |
DTR | 20 | DTR | Data Terminal Ready Input to modem from DTE to |
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| control answering and disconnection of modem. |
MT5600BA/BL Series User Guide | 62 |