ls /devand look for cuaU*.* ports and ttyU*.* ports.
cu -l /dev/ttyU0.2
There are no OS tools to show a SIM slot.
usbconfig ugen1.3 ugen1.3: <Sierra Wireless, Incorporated MC7700> at usbus1, cfg=0 md=HOST spd=HIGH (480Mbps) pwr=ON (0mA)
Theoretically you could use a cellular modem in this slot.Optional Wireless card kit is available from Protectli. Card is USB Channel and fits in a designated PCIe form factor slot with USB communications