IF YOU ARE MIGRATING FROM AC24AT, AC422AT, OR AC37 CARDS
PCI-AC48 User’s Guide
12
•
Belden Wire and Cable: 9,729
You may also be able to use Category 5 solid cable (any manufacturer). Shielded Category 5 cable
offers better noise immunity. Maximum distance has not been tested.
If You Are Migrating from AC24AT, AC422AT, or AC37 Cards
If you are replacing existing Opto 22 AC24 or AC37 adapter cards with new PCI-AC48 cards, note
that the PCI-AC48 does not have RTS and CTS capability. Also, you should be aware of a potential
compatibility problem.
Because the AC48 is a PCI card, its UART registers are not located at the traditional locations typically
used for COM1 through COM4. PCI and ISA buses operate differently: the ISA bus can specify an I/O
port address so the adapter card can communicate directly with the port, but the PCI bus works
from a card ID that is assigned when the card is installed in a PCI slot.
The way in which existing drivers and software address the adapter card determines their
compatibility with the PCI-AC48.
Software that uses Windows’ drivers by referencing logical device names will be compatible with
the PCI-AC48, since the card’s Windows-compatible drivers allow it to be mapped to a logical COMx
device name.
Some Opto 22 drivers and software offer the option of using logical device names for COM ports.
This option is sometimes misleadingly designated as RS232 Port instead of WindowsCOMx drivers.
For example, in the utility program shown below, you would set the logical port by choosing the
Port Type RS232 Port and then choosing the correct Port Number.
Choose RS232 Port
Choose correct COM port
