How do I connect serial devices to Macs which do not have serial ports?

Technical Note: 248
Reads: 15139
Creation Date: 25/09/2001
Modification Date: 12/02/2004

Improvision recommends two adapters supplied by Keyspan (www.keyspan.com). The most appropriate adapter to use may depend on the type of interface cable being used with the serial device.

The serial device may be supplied with a cable suitable for connecting to either a PC serial port or a Mac serial port. The end of the cable which plugs into the computer will be a 9 pin D type connection for a PC serial cable and an 8 pin round MINI DIN for a Mac serial cable. Not all equipment manufacturers will supply Mac cables with their hardware. Improvision can only provide one type of serial cable, that being a Mac serial cable for Zeiss or Leica electronic microscopes and for the Orbit 1 controller. For all other devices the cable must be supplied by the manufacturer. The Keyspan website provides pictures of both adapters for those who wish to visually compare shapes of connections.

1. USB to twin (Mac) serial adapterFor connecting Mac serial cables to USB ports, the Keyspan USB to twin serial adapter (Keyspan part number USA28X, Improvision part number 284) is used. This adapter provides two serial ports numbered 1 and 2 from one USB port. A free USB port on the Mac is therefore required. Devices may be plugged into either or both ports.

To use this adapter the correct drivers must be loaded. Drivers are available for both Mac OS 9 and X. To install the drivers use one of the following options:1. Use the installer on the CD which came with the adapter. 2. Download the relevant drivers from the Keyspan website (www.keyspan.com).3. Use the Keyspan installer from the "Hardware Drivers" folder on the Openlab CD4. Download "Openlab Hardware Drivers Pack" from the Improvision website downloads page.

Double - click the installer to run it and follow the on screen instructions.

Once the drivers are installed, the device is connected using the serial cable, via the adapter to the computer. Remember or note the number of the port as written on the Keyspan adapter that each device is plugged into. Switch the device on and start-up Openlab.

The Openlab preferences must be configured before Openlab will recognise and start communicating with the device.

In Openlab, open the Preferences dialog. In the Preference dialog chose the option for Serial ports from the list on the left hand side. For the name of each device choose the correct port from the pop-up list.

The driver does not give the ports the same name in the pop-up list as physically written on the side of the adapter.

Port 1 is called Printer Port USB in software

Port 2 is called P#2USA28X013 (or similar) in software

For some of the Openlab interfaces (palettes) you will need to select the correct device in the palette. Such palettes will have a menu, called Device, on them from which the correct hardware is selected.

2. Keyspan USB to 4 port (PC) serial adapterFor connecting PC serial cables to USB ports the Keyspan USB 4 port serial adapter (Keyspan part number USA-49W, Improvision part number 1837) is used. This adapter provides four serial ports numbered 1, 2, 3 and 4 from one USB port. A free USB port on the Mac is therefore required. Devices may be plugged into any port.

To use this adapter the correct drivers must be loaded. Drivers are available for both Mac OS 9 and X. To install the drivers use one of the following options:1. Use the installer on the CD which came with the adapter. 2. Download the relevant drivers from the Keyspan website (www.keyspan.com).

Double - click the installer to run it and follow the on screen instructions.

Once the drivers and the adaper are installed connect the device, using the serial cable, via the adapter to the computer. Remember or note the number of the port as written on the Keyspan adapter that each device is plugged into. Switch the device on and start-up Openlab.

The Openlab preferences must be configured before Openlab will recognise and start communicating with the device.

In Openlab, open the Preferences dialog. In the Preference dialog chose the option for Serial ports from the list on the left hand side. For the name of each device choose the correct port from the pop-up list.

Troubleshooting

1. Although drivers and adapter are installed Openlab cannot detect serial devices.

Solution: Check the device is physically connected.

Assign serial ports to devices as detailed in the main body of this technical note.

Check the session log. File>Show Session Log. If messages appear that a port could not be opened for a device because it is in use try restarting the computer to clear the ports.

2. A device plugged into Port 2 of the USB to twin serial adapter can be configured within Openlab but one plugged into Port 1 is not detected. Both are set up correctly in the Preferences.

Solution:

Open the Keyspan Manager or Serial Assistant Control Panel under the Apple menu. Open the Apple Menu > Control Panels>Keyspan USA 28x Manager or Keyspan USA 28X Serial Assistant

In the dialog box ensure that Port 1 is selected and that "Emulate Printer" is unchecked. You may need to click an "Advanced Settings" button to find the dialog where printer port emulation may be turned off.

If you are using Mac OS 9.0.2 you will need to upgrade to OS 9.0.4 or later as a known compatibility issue between Mas OS 9.0.2 and Keyspan adapters prevented Port 1 from being accessed. Improvision recommends that users of Openlab always run with the latest available version of OS9.

3. No port choices are listed in the pop-up next to the device name in the serial port preferences. The message "Un-named USB device driver could not be found" appears after restarting the machine.

Solution: The drivers for the Keyspan adapter are not installed, have not been installed properly or are not the correct version. Try reinstalling the drivers, making sure you are using one of the installers described above and follow exactly the instructions given on screen by the installer. Then check the Keyspan website (www.keyspan.com) for the latest drivers recommended for the model of adapter you have. For example the first available version of the USB to twin serial adapter was opaque white plastic and required drivers named "USB Serial Adapter - USA-28".