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GeoPort Mini-DIN-9

A Mini-DIN-9 GeoPort

GeoPort was an enhanced Mini-DIN-9 serial data port available on Pippin consoles, as well as with Apple's Power Macintosh computers of the time.[1]

FunctionalityEdit

The serial ports on Pippin consoles are controlled by a Zilog Z85C30 Serial Communication Controller,[2] capable of LocalTalk speeds up to 230.4 kbps. Many early Macs typically had two Mini-DIN-8 serial ports, labeled for a printer and modem.[3] The GeoPort specification adds a 9th pin to the serial port to supply 5 volts of DC power. A GeoPort is backwards-compatible with standard Mini-DIN-8 serial devices, but 9-pin peripherals cannot be plugged into an older 8-pin serial port.[4]

Attaching a GeoPort Telecom Adapter to a GeoPort-ready serial port (labeled with a globe symbol on Pippin consoles) allows it to emulate and function as a (relatively) low-cost modem without an external power supply, at the expense of CPU overhead.[1] The GeoPort's functionality was also integrated into Apple's proprietary Comm Slot II in some PowerPC-based Macintosh desktop computers, but has since been discontinued.[5]

Telecom Adapter modelsEdit

GeoPort Telecom Adapters shipped with varying modem connection speeds, and could be upgraded through software updates. Using one on a Pippin console would require a "Pippinized" CD-ROM that includes support for use of the GeoPort.[1]

  • GeoPort Telecom Adapter M1694LL/B - 14.4 kilobaud (kbps)
  • GeoPort Telecom Adapter (II) M2117LL/A - 28.8 kilobaud (kbps)
  • GeoPort Telecom Adapter II M5438LL/A - 33.6 kilobaud (kbps)

Telecom Adapters vs conventional modemsEdit

Pippin Atmark consoles in Japan shipped with an actual 14.4 kilobaud modem (PA-82007) which was not a GeoPort Telecom Adapter, thus reducing CPU overhead. However, its attached 9-pin connector cable was capable of drawing power from the GeoPort and did not require an external power supply. Pippin @WORLD consoles in the United States shipped with a re-branded 28.8 kilobaud Motorola ModemSURFR, which came with its own separate power supply.[6] Some third party manufacturers, such as Global Village, also created conventional modems that could draw power from the 9th pin of GeoPort-equiped Macs to eliminate the need for a power supply, like Pippin modems.[4]

GalleryEdit

ReferencesEdit

  1. 1.0 1.1 1.2 GeoPort 'Modems' by Daniel Knight, Low End Mac. 1998-04-10.
  2. Apple’s Pippin and Bandai’s @World: Missing the Mark(et), Low End Mac. 2006-09-22.
  3. Macintosh Serial Throughput by Daniel Knight, Low End Mac. 1998-04-12.
  4. 4.0 4.1 Making a Universal Teleport Gold IIP modem. by James Lockman.
  5. Apple's Geo Modem, The 6400 Zone. 2003-06-17.
  6. Les modems de la Pippin (French) by Pierre Dandumont, Journal du Lapin. 2016-09-24.

See alsoEdit

External linksEdit