Hello everybody. I had a problem with routerboard 112 and modem. I’m trying to configure a ppp-client. After I do “enable” configured connection nothing happened. The status of connection becomes running but the modem does not try to call. Monitoring of connection speaks status: " reseting link… " At the same time if to try to call “by hand” through “system serial-console serial0” all works. What’s it? 
Share your configuration if you want others to help.
Ok, here is my config
[admin@MikroTik] > interface ppp-client print
Flags: X - disabled, R - running
0 X name="ppp-out1" max-mtu=1500 max-mru=1500 port=serial0 user="ppuser"
password="qwerty" profile=default phone="xxxxxxx"
dial-command="ATDT" modem-init="" null-modem=no dial-on-demand=yes
add-default-route=yes use-peer-dns=yes allow=pap,chap,mschap1,mschap2
, where xxxxxxx - phone of my modem pool.
dial-on-demand should be “no” in most cases, serial0 by default is used by the serial console, and modems usually require some init string to function properly. Just a few reasons why it doesn’t work.
Eugene
It doesn’t work neither with dial-on-demand=yes nor with dial-on-demand=off. I now that serial0 used by console by default. Console certainly disabled on serial0 port, otherwise “interface ppp-client enable 0” doesn’t work. As regards a modem-init, its presence or absence does not affect on modem behaviour.
I wish to emphasize that the call manually through the “system serial-console serial0” passes on hurrah.