I have a USB modem that worked fine under Mojave. With Big Sur (11.2.3), the device is not recognized immediately after a restart (/dev/cu.usbmodem123456781 does not exist). However, if I unplug the device and then replug into the USB port, /dev/cu.usbmodem123456781 exists and can be used. I'm accessing the device programmatically in a macOS app, using Objective-C.
After a restart, System Report correctly lists the USB modem (even before unplug/replug) as follows:
USB Modem:
Product ID: 0x1340
Vendor ID: 0x0572 (Conexant Systems, Inc.)
Version: 1.00
Serial Number: 12345678
Speed: Up to 12 Mb/s
Manufacturer: Conexant
Location ID: 0x14110000 / 5
Current Available (mA): 500
Extra Operating Current (mA): 0
What can I do so that /dev/cu.usbmodem123456781 exists after a restart?
After a restart, System Report correctly lists the USB modem (even before unplug/replug) as follows:
USB Modem:
Product ID: 0x1340
Vendor ID: 0x0572 (Conexant Systems, Inc.)
Version: 1.00
Serial Number: 12345678
Speed: Up to 12 Mb/s
Manufacturer: Conexant
Location ID: 0x14110000 / 5
Current Available (mA): 500
Extra Operating Current (mA): 0
What can I do so that /dev/cu.usbmodem123456781 exists after a restart?
