Known bugs

	1) SMS sending charset problem
		solved by PDU
2) HW: Terminate (from both side) active call break voice on all held

3) HW: Terminate held call locally break voice on all active

4) HW: Issue AT+CHLD=1x command before receiving ^CONF:call_idx after successfull ATDnum; 
kill device. Device not responding on commands but still sending ^BOOT: and ^RSSI: URCs

5) HW: device hangup after entering long PDU

6) white noise on x86_64

7) Some characters wrong encoded for SMS
	think iconv and localization trouble

8) command removed from queue by timeout when response already in read buffer

9) cpvt locking

10) HW device reboot and chan_dongle crash on receive long SMS in TEXT UCS2 mode (>150 symbols)

	11) DTMF not send ?

	12) zombi calls

13) HW: device still in sms prompt infinite (only 0x1B can help) if entered more 133 symbols in TEXT UCS-2 mode

14) Sometimes device stops responding to commands

	15) SIGSEGV on hangup
