Hi all, I'd appreciate any opinions about Q950 serial port's configuration. Basically, I've two questions:
1)- Is there any advantage in using "Faster" setting in Serial Switch control panel? What exactly it does to the serial ports? I've found such information on the Web: === Technical Q&A DV25: Setting Port Speed on a Modem Port by Apple http://216.239.37.100/search?q=cache:PX4viWB3kHkC:developer.apple.com/qa/dv/dv25.html+%22serial+switch%22+%22control+panel%22&hl=en&ie=UTF-8 The Macintosh IIfx, Quadra 900 and 950 models have a simple IOP architecture which offloads some of the SCC interrupt handling operations from the CPU. The Zilog SCC is combined into a custom chip and is not directly available. These are the machines that have the Serial Switch control panel: it allows native operation of the IOP/SCC for best performance, and emulates the Zilog SCC interface when set into Compatible mode for those few applications that access the SCC directly. The Serial Driver for these machines remains interrupt driven and must respond to IOP/SCC interrupts via the CPU. === Open Transport 1.1.2 Read Me - Part 2 http://www.gla.ac.uk/~gwm1h/ot/ot1.1.2/OT_1.1.2_ReadMe-Part2.html On a IIfx or a Quadra 950, Open Transport can only use the "compatible mode" setting in the Serial Switch control panel. Don't use the "faster mode" setting with LocalTalk. === Virtually all the serial communication-related software I've seen, suggests to disable that 'faster' mode (including even my Epson Stylus Photo 700 printer driver!), and I'm wondering if there are any applications capable to use it... 2)- Is there any advantage in using 'GPi' input on the Q950 serial ports? The information I've found on the Web is a bit contradicting: === Ports and Pinouts Service Source by Apple http://www.apple.com.pl/infotech/varia/Ports/Ports_Pinouts.pdf 7 General-purpose input On serial port A (modem), if the VIA1 SYNC signal is high, this input will be routed to the receive/transmit clock input of the SCC. This clock input supports high-speed synchronous devices. === MacSLIP by Hyde Park Software, Inc. User's Manual http://www.id.unizh.ch/services/pc-mac-support/mac-sys/macsoftware/macslip/manual30.pdf If your Macintosh supports the GPi serial input line, and that line is wired in your modem cable to your modem's data carrier detect line, MacSLIP will detect carrier loss (an on to off transition of the GPi signal) and automatically go into the disconnected state. If the DCD indicator is dimmed (grayed out), your Macintosh does not support the GPi input, or in the case of systems with a serial IO processor such as the IIfx or Quadra 950, your serial port is in "faster" mode and GPi cannot be used. === From: Apple Tech Library Article Created: 21 February 1995 Subj.:What is GPi? http://www.ccr-computerclub.de/lam2/gpi.htm In Macintosh software, the choice of using GPi is up to the programmer of the software. The software producer should tell you in the documentation whether their software relies on GPi and other configuration information. In most Macintosh serial communications software, the use of GPi is minimal or non-existent. A few Macintosh computers (such as the Macintosh IIfx and Macintosh Quadra 950) are exceptions to certain hardware trends and require the use of special compatibility software to allow the use of communications software that require GPi control. === Does Ports and Pinouts Service Source's phrase "On serial port A (modem)" means that GPi is supported on the 'Modem' port only, and absent on the 'Printer' port? What "special compatibility software" required to use that pin? On many 'Mac modem cables', the GPi pin is connected to the Data Carrier Detect signal - does it actually works on Quadra? Thanks, Artur -- Quadlist is sponsored by <http://lowendmac.com/> and... Small Dog Electronics http://www.smalldog.com | Enter To Win A | -- Canon PowerShot Digital Cameras start at $299 | Free iBook! | Support Low End Mac <http://lowendmac.com/lists/support.html> Quadlist info: <http://lowendmac.com/lists/quadlist.shtml> The FAQ: <http://macfaq.org/> --> 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/quadlist%40mail.maclaunch.com/> Using a Mac? Free email & more at Applelinks! http://www.applelinks.com
