The Sony CMD-J5 (and the closely related CMD-J16) exposes a 12-pin flat I/O connector on the base of the phone. It carries the charging contact, an RS-232 serial interface used by the QN-3RS data cable, a single-ended audio in/out pair, and accessory identification. The same connector is used across the Sony CMD-J5/J6/J7/J70 family.
| Pin | Signal | Description |
|---|---|---|
| 1 | GND | Ground — digital interface and charger return current |
| 2 | Charge | Positive charging contact |
| 3 | GEN I/O | General-purpose I/O to the baseband chip (in/out/interrupt) |
| 4 | Power Out | Accessory power / external Vbat indication |
| 5 | RX (in) | RS-232 receive data (into the phone) |
| 6 | TX (out) | RS-232 transmit data (from the phone) |
| 7 | ACC ID | Accessory present / analogue accessory ID |
| 8 | RS232 RTS | Request to send (also labelled RFR) |
| 9 | RS232 CTS | Clear to send |
| 10 | Audio Out | Single-ended audio output (0.8 Vpp into 1 kΩ) |
| 11 | Audio In | Single-ended audio input (max sensitivity 365 mVrms) |
| 12 | AGND | Audio ground (reference for Audio In and Audio Out) |
Signals
- GND — ground return for the digital interface and for charger current.
- Charge — positive contact for the charging function; an accessory with an active charge wakes the phone.
- GEN I/O — connected to a general-purpose I/O pin on the baseband digital chip; can be assigned as input, output or interrupt per accessory.
- Power Out — accessory supply; in a car-kit it indicates an accepted/in-progress call so the kit can power its audio section.
- RX / TX — the RS-232 serial data pair used by the QN-3RS data cable (RX into the phone, TX out of the phone).
- ACC ID — signals the presence of an accessory and provides an analogue ID identifying it.
- RS232 RTS / CTS — hardware flow-control lines of the RS-232 interface.
- Audio In / Audio Out — single-ended audio interface to a headset or hands-free kit, referenced to AGND.
- AGND — analogue ground reference for the audio signals.
References
- Sony CMD-J5/J16 Service Manual — Accessory Interface connector (§2.8) — Sony Corporation.