The Metricom Ricochet SE is a wireless modem that presents a Hayes-compatible DCE interface to the host computer. The Macintosh end of this cable uses the standard mini-DIN-8 female connector introduced with the Macintosh Plus (1986), wired in unbalanced RS-232-compatible mode: only the TxD− and RxD− lines of the RS-422 differential pairs are used, with RxD+ tied to ground to bias the differential receiver. The Ricochet SE modem end uses a 14-pin proprietary connector unique to the SE model; the SX variant uses a different proprietary connector and is not interchangeable with this cable.
8 pin mini-DIN female connector
14 pin Ricoshet SE connector
Notes
The mini-DIN-8 connector is keyed and polarised; it cannot be inserted incorrectly. On the Macintosh, the modem port is identified by a telephone icon. Both the modem port and the printer port are electrically identical RS-422 interfaces controlled by the Zilog Z8530 Serial Communications Controller (SCC); either port may be used, though the modem port is conventional for external modems. The Ricochet SE proprietary 14-pin connector is specific to the SE model and differs from the connector used on the Ricochet SX; cables for the two models are not interchangeable. Metricom did not publish a public specification for the proprietary modem connector.
References
- Guide to the Macintosh Family Hardware, Second Edition — Apple Computer / Addison-Wesley, 1990
- Inside Macintosh: Devices — Serial Driver — Apple Computer, 1995