| Palm Serial Connector | |
| Type: | Communication, power supply |
| Superseded By: | Palm Universal Connector |
| Num Pins: | 10 |
| Pin1: | RS-232 |
| Pin1 Name: | DTR output nonstandard |
| Pin2: | VCC |
| Pin2 Name: | +3.3 V |
| Pin3: | RxD |
| Pin3 Name: | RS-232 input, Signal T RxD |
| Pin4: | RTS |
| Pin4 Name: | RTS RS-232 output |
| Pin5: | TxD |
| Pin5 Name: | RS-232 output, Signal R TxD |
| Pin6: | CTS |
| Pin6 Name: | CTS RS-232 input |
| Pin7: | HOTSYNC |
| Pin7 Name: | HotSync IRQ - +3.3 V to press the HotSync button |
| Pin8: | ID |
| Pin8 Name: | Peripheral id. The Palm modem connects this pin to pin 2 to 20 kOhms ID |
| Pin9: | N/C |
| Pin9 Name: | is not connected. In the Palm III, 5 V DC output |
| Pin10: | GND |
| Pin10 Name: | Signal Ground |
The Palm Serial were 3 successive proprietary 10-pin Serial connectors on the bottom of the first 3 series of models of PDAs from Palm, Inc. to provide serial communications: 1) pre-IrDA models; 2) the 1st IrDA models; 3) the 1st thin, metal-body models. In addition to Palm's models (and rebranded models like the IBM WorkPad series) similar serial connectors have been used in the Ericsson MC16 Palmtop and Handera equipment.Pressing the HotSync button located at the base of the cradle closes a circuit between pins 2 and 7 which causes the activation of MUN2214 NPN transistor connected to pin 38 of the Motorola Dragonball CPU that provides a low signal on the IRQ1 UART, triggering the HotSync process.On pin 8 when a modem connects to the Palm similarly closes a circuit pin 2 to activate another MUN2214 NPN transistor connected to pin 32 (GPIO UART) of the CPU to notify the presence of the modem.