/usr/share/smstools/conf-templates/smsd.modem.template is in smstools 3.1.15-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 | [@DEVICENAME@]
init = @INIT@
device = @DEVICE@
incoming = @INCOMING@
pin = @PIN@
baudrate = @BAUDRATE@
|