At 10:37 PM -0500 9/19/2002, Jeff Walther wrote: > >Date: Thu, 19 Sep 2002 15:12:55 -0700 >>From: "Robert P. Mcallister" <[EMAIL PROTECTED]> > >>Just out of curiosity, what is the 60-pin male connector below the PCI >>slots on the 7500 motherboard for? There is a two-prong connector below >>it labeled "Geoport Clock." Are both for the dreaded Geoport modem? > >I don't know about the 60 pin connector, but the Geoport Clock is >unrelated to the Geoport modem. A little known fact about the >Geoports is that while their nominal speed is 115 Kbps (or is it 230 >Kbps?) they can supposedly do a couple megabits per second if an >external clock signal is supplied. The Geoport Clock jumpers are >for that external signal. I don't know if anyone ever built any >hardware to take advantage of this capability. The only place I'd >expect to see it would be in lab or automation equipment.
IIRC the original Mac serial port on the Mac128K was rated for 1MB/S when externally clocked. Some of the first harddisks for Macs used the serial port clocked at a high speed. There was a product that made use of it but didn't see much use. It was a faster LocalTalk network adapter. It connected in place of or in line with the standard LocalTalk or PhoneNet adapter. It used an external Digital Phase Locked Loop (DPLL) operating at around 700KBps. It could interoperate with conventional LocalTalk, slowing down to 230.4KBps when talking to printers, Macs without the special adapter or other LocalTalk devices. -- Clark Martin Redwood City, CA, USA Macintosh / Internet Consulting [EMAIL PROTECTED] "I'm a designated driver on the Information Super Highway" -- PCI-PowerMacs is sponsored by <http://lowendmac.com/> and... Small Dog Electronics http://www.smalldog.com | Refurbished Drives | -- Sonnet & PowerLogix Upgrades - start at $169 | & CDRWs on Sale! | Support Low End Mac <http://lowendmac.com/lists/support.html> PCI-PowerMacs list info: <http://lowendmac.com/lists/pci-powermacs.shtml> --> AOL users, remove "mailto:"; Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive:<http://www.mail-archive.com/pci-powermacs%40mail.maclaunch.com/> Using a Mac? Free email & more at Applelinks! http://www.applelinks.com
