Hi Denis,

With Nokia E51 AT+CHLD=11 returned ERR0R, AT+CHLD=0 and ATH returned OK
however they did not have effect to the call. AT+CHUP returned OK and
call was terminated (Caller received busy signal).

RING
AT+CHLD=11
ERROR

RING

RING
AT+CHLD=0
OK

RING

RING
ATH
OK

RING

RING
AT+CHUP
OK

Regards,
Marko