I found GSM modems but strange behavior is present. Comm port is 5

oComm = CREATEOBJ('MsCOMMLib.Mscomm')
oComm.CommPort = 5
oComm.PortOpen = .T.
oComm.settings = "9600,N,8,1"
oComm.inputLen = 0

on command

oComm.Output = "AT" + Chr(13) + Chr(10)

error appear Ole IDispatch exception code 0 from MSComm: Operation valid only when the port is open.

What am I doing wrong? Port is open or not?
Simple thing can be terrific.