Thank you for having responded. The modem is plugged in and turn on the workstation.
# cat /var/log/messages
May 5 10:14:14 wf kernel: ugen4.2: <GCT SEMICONDUCTOR Inc> at usbus4
May 5 10:14:14 wf kernel: umass0: <GCT SEMICONDUCTOR Inc Modem Yota, class 0/0, rev 2.00/1.00, addr 2> on usbus4...