Keyspan USA-19 - Manual (Page 4)

'classic' Mac OS Serial Ports & Serial Devices
Serial devices under the 'older' Mac OSes (Mac OS 8.x-9.x) access serial ports via the following
software:
the Chooser (ie printers)
applications (ie Palm Pilots)
Control Panels (ie Wacom tablets)
Regardless of which software you used, your serial device was communicating with software
libraries that handled the very low level communications between your serial device hardware and
your serial port. These low level software libraries (specifically: Communications Resource
Manager (CRM), CommToolBox (CTB), and OpenTransport) are unique to the 'older' Mac
OSes and are not found on Mac OS X.
Unfortunately, 'older' serial programs cannot communicate with Mac OS X serial ports. Therefore,
if your serial device's software only works on a 'older' Mac OSes, installing the USB Serial Adapter
software for Mac OS X will not make your serial device work under Mac OS X.
If your serial device's software only runs in 'classic' Mac OSes, you have several options:
1. Try to get your serial device to work using your existing 'classic' hardware and
software (the hardware and software that ran on Mac OS 8.1 through 9.x) via Mac
OS X CLASSIC environment. If this does not work, please try option 2.
2. Boot into Mac OS 9.x and use your serial device from there.
Keyspan, Mac OS X Serial Ports & Serial Devices
Serial devices that run natively on Mac OS X access serial ports via the following software:
System Preferences
Mac OS X applications
terminal applications
Regardless of which method is used, your serial device communicates with a software library called
POSIX (aka POSIX API).
When a Keyspan adapter is connected, the Keyspan USB Serial Adapter software for Mac OS X
registers a port with the IORegistry (this is another software library). At this point, a program can
get the list of available serial ports (including Keyspan serial ports) from IORegistry. Once the
program has the list available serial ports, the program uses the POSIX API to communicate with
the serial port.
(continued on next page...)
Keyspan:USB Serial Adapter for Mac OS X-v2.x User Manual
This User Manual applies to the Keyspan USB Serial Adapter Software for Mac OS X.
Rev 05jul15 Page 4