Comment # 7 on bug 968573 from Martin Pluskal

(In reply to Dieter Jurzitza from comment #6)
> Could you kindly shed some light on this, too? Things are going well if I
> delete the reference to 
> BindsTo=dev-%i.device
> from within mgetty@service, so, "ttyS4" is acceptable, a link "modem->ttyS4"
> is not? How would I ensure the apropriate device to get selected?
> 
> Thanks again - and, finally, could someone provide a pointer where to get
> this information from? The documentation is difficult to seek for this.
It means that it depends on said device (i.e. ttyS4), while /dev/modem is I
assume not considered as a device: I guess that while "systemctl status
dev-ttyS4.device" will show you something like:
��� dev-ttyS4.device - /dev/ttyS4
   Follow: unit currently follows state of
sys-devices-platform-serial8250-tty-ttyS4.device
   Loaded: loaded
   Active: active (plugged) since Sat 2016-02-27 11:20:32 CET; 1 day 9h ago
   Device: /sys/devices/platform/serial8250/tty/ttyS4

"systemctl status dev-modem.device" will not