Reading from Serial Port always times out - vb.net

Question

I am writing software for a POS terminal. This terminal has a printer that is attached to a cash drawer. I need to send a code to the printer, and listen for what is returned to determine whether or not the cash drawer is open. Using MSComm, I had logic that worked in VB6, so I know the actual Hex code I am sending is correct.
This code always returns "Error: Serial Port read timed out". I do not know what I am doing wrong with the read portion. Please advise, how do I listen for what the port is sending back as a response?
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
' Receive strings from a serial port.
Dim returnStr As String = ""
Dim x As Integer = 0
Dim com3 As IO.Ports.SerialPort = Nothing
logfile.WriteLine("STARTCASHDRAWERSTATUSCHECK")
Try
com3 = My.Computer.Ports.OpenSerialPort("COM3")
com3.WriteLine(ChrW(&H1B) & ChrW(&H75) & ChrW(&H0))
com3.BaudRate = SetPortBaudRate(9600)
com3.Parity = IO.Ports.Parity.None
com3.DataBits = SetPortDataBits(8)
com3.StopBits = SetPortStopBits(1)
com3.Handshake = IO.Ports.Handshake.RequestToSend
com3.ReadTimeout = 10000
Do
x = x + 1
Dim Incoming As String = com3.ReadLine()
logfile.WriteLine(x & "incoming" & Incoming & "x")
If Incoming Is Nothing Then
logfile.WriteLine("Button2resultEXITDO" & x)
Exit Do
Else
returnStr &= Incoming & vbCrLf
End If
If x > 10 Then
Exit Do
End If
Loop
Catch ex As TimeoutException
returnStr = "Error: Serial Port read timed out."
Finally
If com3 IsNot Nothing Then com3.Close()
End Try
logfile.WriteLine("Button2result:" & returnStr)
End Sub
Thanks in advance!