...
set interfaces cl-1/0/0 traceoptions flag all
set interfaces cl-1/0/0 dialer-options pool 1 priority 100
set interfaces cl-1/0/0 cellular-options sim 1 select-profile profile-id 1
set interfaces cl-1/0/0 cellular-options sim 1 radio-access lte-only
...
set interfaces dl0 unit 0 family inet negotiate-address
set interfaces dl0 unit 0 family inet6 negotiate-address
set interfaces dl0 unit 0 dialer-options pool 1
set interfaces dl0 unit 0 dialer-options always-on
set interfaces dl0 unit 0 dialer-options dial-string 1234
...