I took me quite some time to figure this out (again). Actually, the solution was already provided in one of my posts from 2008 but I had completely forgotten about it. I recently downloaded the new 64-bit USBtoUART SiLabs driver (the package contains a 32-bit driver too) to hook up my Holux M-241 GPS logger to a USB port on my Mac. Every time I tried to connect the GPS client software BT747 to the Holux data logger I received the following exception:
22158 - Classgps.connection.GPSRxTxPort Error: Port /dev/cu.SLAB_USBtoUARTis currently in use gnu.io.PortInUseException: Unknown Application at gnu.io.CommPortIdentifier.open(CommPortIdentifier.java:467)
The solution is to create the semaphore directory for the RxTx Java library which BT747 relies upon:
sudo mkdir /var/lock && sudo chmod 777 /var/lock
Be sure to set the baud rate down to 38400 in BT747 or you won’t be able to establish a connection.
By the way, does anyone now the difference between the Holux M-241 and the new Holux M-241c? The tech specs seems to be pretty much identical.