gsms_router:send([{addr,"<number>"}], "Hello").
{ok,Ref} = gsms_router:subscribe([]).
Pdu = receive {gsms,Ref,Pdu1} -> Pdu1 end.
Text = Pdu#gsms_deliver_pdu.ud.
Setup internal serial port /dev/ttyAMA0 for use as modem or other serial com line then ttyAMA0 must be disable in /etc/inittab
# comment out in /etc/inittab
# T0:23:respawn:/sbin/getty -L ttyAMA0 115200 vt100
Also remove rerences to ttyAMA0 in /boot/cmdline.txt If cmdline looks like
dwc_otg.lpm_enable=0 console=ttyAMA0,115200 kgdboc=ttyAMA0,115200 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline rootwait
After change it should look like
dwc_otg.lpm_enable=0 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline rootwait