Serial Cable for Old HP-48G Series
Looking at back of HP-48:
Connect your HP-48GX, HP-48G+, HP-48G, HP-48SX, or HP-48S to your computer with this high quality 9 pin (PC) to 4 pin (Calc) serial cable. This cable is not suitable for any other calculators except those listed above.
---------
| 1 2 3 4 |
\_______/
Here are the pinouts for the HP-48G serial port:
4 3 2 1
/------------|-|-|-|----\
| 48SX | Pin Function Std RS232 pin
| ___________________ |
| | | | 1 Chassis Ground 1
| | 4: "THIS" | | 2 Transmit Data 2
| | 3: "IS" | | 3 Receive Data 3
| | 2: "THE" | | 4 Signal Ground 7 (DB25)
| | 1: "SCREEN" | | or 5 (DB9)
| ------------------- | DB25 = 25 pin connector
| | DB9 = 9 pin connector
| [A] [B] [C] [D] [E] [F] |
| MTH PRG CST VAR ^ NXT |
| . . . . . . |
HP-48 pin RS232 pin
CHG 1 - - - - - - - - 1 CHG Chassis ground does not
actually have to be connected.
TX 2 --------------- 2 TX
RX 3 --------------- 3 RX
GND 4 --------------- 7 GND (DB25) or 5 (DB9)