VT102 User Guide| Chapter 6 | Contents |
| Pin | Name (Mnemonic) | CCITT / EIA | Switch | Description |
|---|---|---|---|---|
| 1 | Protective ground (PGND) |
101/AA | - | Connects to terminal chassis. Also connects to external ground through third wire of power cord. |
| 2 | Transmit data (TXD) |
103/BA | S6 | From VT102: When switch S6 is on (closed), TXD transmits serial characters and breaks generated by terminal. TXD is in mark state when no characters are transmitted. |
NOTE: When S6 is on (closed), switch S7 must be off (open). |
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| 3 | Received data (RXD) |
104/BB | - | To VT102: RXD receives serial characters from the computer. |
| 4 | Request to send (RTS) |
105/CA | S1 | From VT102: When switch S1 is on (closed), RTS is on if terminal is on-line and off if terminal is off-line. |
| 5 | Clear to send (CTS) |
106/CB | S2 | To VT102: When switch S2 is on (closed), CTS is only used to turn CTS indicator on or off. The on condition of CTS turns CTS indicator on; the off condition turns CTS indicator off. |
NOTE: When S2 is on (closed), switch S3 must be off (open). |
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| 6 | Data set ready (DSR) |
107/CC | - | To VT102: DSR turns DSR indicator on or off. The on condition of DSR signal turns DSR indicator on; the off condition turns DSR indicator off. |
| 7 | Signal ground (SGND) |
102/AB | - | SGND is common ground reference potential for all connector signals except protective ground. SGND connects to protective ground conductor. |
| 20 | Data terminal ready (DTR) |
108.2/CD | - | From VT102: DTR is on when the terminal is on-line and off when the terminal is off-line or performing a line disconnect. When on, the modem can usually answer calls (modem auto answer option). When off, the modem usually disconnects and does not answer calls. |
| 23 | Speed select (SPSD) |
111/CH | S10 | From VT102: SPSD is on when the receive speed SET-UP feature selection is greater than 600 baud. SPSD is off when the speed is 600 baud or less. |