Many users of the LocalTalk PC Card have found that if the IBM PC has two
serial ports, each serial port uses an IRQ, and that the PC itself uses the
third one - leaving none available for the LocalTalk PC Card.
The best solution is to move one of the IRQ lines coming from one of the
serial ports (examine the manufacturer's instructions before doing this)
to an IRQ number that can't be used by the LocalTalk PC Card - like IRQ 5.
Then, the LocalTalk PC Card can use the newly-available IRQ line 2, 3, or
4.
Users who have installed LocalTalk PC cards in IBM PC-ATs find that nearly
all of the IBM PC-ATs use both COM1 and COM2. So, using IRQ priority
level 4 or 3 is not possible, and they are forced to consider using IRQ2 --
but the LocalTalk PC card manual states: "Do NOT use switch 3 (IRQ2) if you
have an IBM PC-AT computer."
Fortunately, if you have AppleShare PC 2.0, this configuration (using IRQ
priority level 2) should work fine.
Quoting the README.DOC file on the AppleShare PC disk:
"The 2.0 version of the LocalTalk PC Card driver (AppleTalk.EXE, included on
this disk) does not use the card's hardware interrupt feature. This means
that the default card settings will not conflict with a COM2 serial port,
as your card manual indicates. The 2.0 driver ignores the /cardint command
line parameter."
Some users of the LocalTalk PC card have reported problems after installing
the card and changing the IRQ (Interrupt Request line). Symptoms have
included:
- When printing to "*", the LaserWriter just hangs.
- Selecting a printer causes the "Looking for AppleTalk Zones" to blink
forever.
- AppleShare hangs also.
- Inter-Poll can't see anything from the outside.
- Reloading software doesn't help.
- Reducing the number of machines on the network doesn't help.
- Changing LocalTalk PC cards doesn't help.
The key is that you must tell DOS when you change IRQs. To do this, put
the command "/cardint=x" in the AUTOEXEC.BAT file of your boot disk, where
x is the new IRQ level (either 2 or 4). Check the LocalTalk PC
card manual under the subtitle "Driver configuration options" for more
information.
Note: The LocalTalk PC Card is now owned, sold, distributed and supported by
Farallon Computing. Search under "Farallon" for contact information.