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Table A-1. EIA-232-D Interconnections
Pin | Signal | Signal Name and Description | |
Number | Mnemonic | ||
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1 | Not used. | ||
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2 | TXD | TRANSMIT DATA - data to be transmitted is furnished on | |
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| this line to the modem from the terminal. | |
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3 | RCD | RECEIVE DATA - data which is demodulated from the | |
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| receive line is presented to the terminal by the modem. | |
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4 | RTS | REQUEST TO SEND - RTS is supplied by the terminal to the | |
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| modem when required to transmit a message. With RTS off, | |
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| the modem carrier remains off. When RTS is turned on, the | |
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| modem immediately turns on the carrier. | |
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5 | CTS | CLEAR TO SEND - CTS is a function supplied to the | |
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| terminal by the modem which indicates that it is permissible | |
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| to begin transmission of a message. When using a modem, | |
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| CTS follows the | |
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| delay. | |
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6 | DSR | DATA SET READY - data set ready is a function supplied | |
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| by the modem to the terminal to indicate that the modem is | |
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| ready to transmit data. | |
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7 | SIGNAL GROUND - common return line for all signals at | ||
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| the modem interface. | |
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8 | DCD | DATA CARRIER DETECT - sent by the modem to the | |
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| terminal to indicate that a valid carrier is being received. | |
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Not used. | |||
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15 | TXC | TRANSMIT CLOCK - this line clocks output data to the | |
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| modem from the terminal. | |
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16 | Not used. | ||
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17 | RXC | RECEIVE CLOCK - this line clocks input data from a | |
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| terminal to a modem. | |
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18,19 | Not used. | ||
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20 | DTR | DATA TERMINAL READY - a signal from the terminal to | |
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| the modem indicating that the terminal is ready to send or | |
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| receive data. | |
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21 | Not used. | ||
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User’s Manual |