David, here is another one. It checks for the com port but will allow you to check for a modem too. It came from a MSFT KB, but I don't remember which one (duh, it's in the code! :0).

*!* Q291535: HOWTO: Find installed modems using Microsoft Visual FoxPro
*!* This article use Mscom32.ocx to detect if any modems are installed
*!* and reports the COM port it is using.
*!* 

PUBLIC oform1

oform1=CREATEOBJECT([MODEMFORM])
oform1.Show
RETURN


**************************************************
*
DEFINE CLASS MODEMFORM AS form


	Height = 128
	Width = 160
	DoCreate = .T.
	AutoCenter = .T.
	BorderStyle = 2
	Caption = [Com Port Test]
	MaxButton = .F.
	MinButton = .F.
	Visible = .F.
	AlwaysOnTop = .T.
	BackColor = RGB(0,0,255)
	Name = [Form1]

	*-- Form array that stores information about available machine com ports.
	DIMENSION acommports[1,2]


	ADD OBJECT ocxCOMM AS MSCOMM_OCX WITH ;
		Top = 101, ;
		Left = 72, ;
		Height = 21, ;
		Width = 38, ;
		Name = [ocxCOMM]


	ADD OBJECT lblava_ports AS label WITH ;
		AutoSize = .T., ;
		FontName = [Verdana], ;
		Caption = [Available COM Ports:], ;
		Height = 16, ;
		Left = 14, ;
		Top = 15, ;
		Width = 133, ;
		ForeColor = RGB(255,255,255), ;
		BackColor = RGB(0,0,255), ;
		Name = [lblAVA_PORTS]


	ADD OBJECT command1 AS commandbutton WITH ;
		Top = 78, ;
		Left = 11, ;
		Height = 27, ;
		Width = 138, ;
		FontName = [Tahoma], ;
		Caption = [\<Test Ports for Modem], ;
		Name = [Command1]


	ADD OBJECT timer1 AS timer WITH ;
		Top = 105, ;
		Left = 12, ;
		Height = 23, ;
		Width = 23, ;
		Enabled = .F., ;
		Interval = 1500, ;
		Name = [Timer1]


	ADD OBJECT lblports AS label WITH ;
		FontName = [Verdana], ;
		Alignment = 2, ;
		Caption = [lblPORTS], ;
		Height = 17, ;
		Left = 42, ;
		Top = 46, ;
		Width = 77, ;
		ForeColor = RGB(255,255,255), ;
		BackColor = RGB(0,0,255), ;
		Name = [lblPORTS]


	PROCEDURE WaitForResponse
		*~ This method loops for the specified
		*~ amount of time calling DOEVENTS().
		*~ This allows time for the modem to respond to the requests.

		LPARAMETERS lnDelayInSeconds

		LOCAL lnStartTime
		lnStartTime = SECO()

		DO WHILE SECO() <= (lnStartTime + lnDelayInSeconds) ;
				AND NOT SECO() < lnStartTime
			DOEVENTS()
		ENDDO
	ENDPROC


	PROCEDURE Error
		LPARAMETERS nError, cMethod, nLine
		*~ In THIS.INIT we loop through 10 COM ports, 
		*~ attempting to open each with the MSCOMM32.OCX control.
		*~ We trap the errors here and if it's an OLE error,
		*~ nError will be 1429 (this came from the control).

		IF INLIST(nError, 1429, 1426)
		*~  Populate an error array and check the OLE message.
			LOCAL aErrArray(1)
			AERROR(aErrArray)
		*~ 	If the error msg was "Invalid Port Number"
		*~  the control tried to open a port that either
		*~  doesn't exist or has nothing on it.
		*~  Set a global var (glBadPort) to .T.
		*~  this var is used in THIS.INIT loop.
			IF [INVALID PORT NUMBER] $ UPPER(aErrArray(3)) or ;
				[UNKNOWN OLE STATUS CODE] $ UPPER(aErrArray(3))
				glBadPort = .T.
			ENDIF
		ELSE
		*~  We experienced a non - OLE error. Report it.
			MESSAGEBOX([Error #: ] + ALLT(STR(nError)) + CHR(13) + ;
				[Message: ] + MESSAGE() + CHR(13) + ;
				[Line with error: ] + ALLT(STR(nLine)) + CHR(13) + ;
				[Method: ] + cMethod)
		ENDIF
	ENDPROC


	PROCEDURE Init
		*~ Var that indicates a non-existent or inactive COM port. 
		*~ This var is flipped by THISFORM.ERROR()
		_VFP.AutoYield=.F.
		PUBLIC glBadPort
		glBadPort = .F.

		LOCAL i, lcGoodPorts
		*~ lcGoodPorts used to build string displayed
		*~ in THISFORM.lblPORTS.CAPTION
		lcGoodPorts = []

		*~ Set initial properties of MSCOMM .OCX
		WITH THIS.ocxCOMM
			.RThreshold = 1
			.SThreshold = 1
			.Settings = [9600,n,8,1]
			.RTSEnable = .F.
			.InputLen = 0
		ENDWITH

		*~ Loop through 10 ports, trying to open each.
		FOR i = 1 TO 10
			WITH THIS.ocxCOMM
				.CommPort = i
				.PortOpen = .T.

		*~      glBadPort set to .T. by THIS.ERROR if the # was bad.
				IF !glBadPort
		*~          Expand the array if i>1. The array is initally 1 row.
					IF i > 1
						DIMENSION THIS.aCommPorts[ALEN(THIS.aCommPorts,1)+1,2]
					ENDIF
		*~          Valid port, so store the port # to the first column 
		*~          and a blank to the second column of the current row
		*~          in THISFORM.aCommPorts. We will use this space later
		*~          in THISFORM.COMMAND1.CLICK() to store return value
		*~          communication with the port.
		*~          Also store the port # to the lcGoodPorts variable.
					THIS.aCommPorts(i,1) = i
					THIS.aCommPorts(i,2) = []
					lcGoodPorts = lcGoodPorts + ALLT(STR(i)) + [  ]
				ENDIF

		*~      Reset glBadPort for next loop.
				glBadPort = .F.
		*~      Close the port if it was opened to avoid error on next try.
				IF .PortOpen
					.PortOpen = .F.
				ENDIF
			ENDWITH
		ENDFOR

		*~ List the valid ports in THISFORM.lblPORTS.CAPTION
		THIS.lblPORTS.CAPTION = lcGoodPorts
		RELEASE glBadPort
	ENDPROC


	PROCEDURE ocxCOMM.OnComm
		*** ActiveX Control Event ***

		*~ CommEvent = 2 means the control received data.

		*~  Store the data the control received to
		*~  the appropriate array row/column.
		*~  The row/column to store to is determined by
		*~  global variable "gnPortNum" which is set in the
		*~  thisform.command1.click() loop.
		WAIT WINDOW "TRACY IS HERE"
		IF THIS.commevent = 2
			THISFORM.aCommPorts(gnPortNum,2) = ;
				THISFORM.aCommPorts(gnPortNum,2) + THIS.INPUT
		ENDIF
	ENDPROC


	PROCEDURE command1.Error
		LPARAMETERS nError, cMethod, nLine
		*~ Trap OLE error from the COMM .OCX


		*~ nError = 1429: we experienced an OLE error. This may
		*~ be because we tried to open or communicate via
		*~ the port and there is a non-standard object attached to
		*~ it (such as a printer). Do nothing here; it's not a modem
		*~ since we cannot open AND communicate with it.
		*~ You may want to enhance this error trap.

		IF INLIST(nError, 1429, 1426)
		ELSE
		*~  We experienced a non - OLE error. Report it.
			MESSAGEBOX([Error #: ] + ALLT(STR(nError)) + CHR(13) + ;
				[MESSAGE: ] + MESSAGE() + CHR(13) + ;
				[LINE WITH ERROR: ] + ALLT(STR(nLine)) + CHR(13) + ;
				[Method: ] + cMethod)
		ENDIF
	ENDPROC


	PROCEDURE command1.Click
		*~ gnPortNum is used in the ONCOMM event of the .OCX
		PUBLIC gnPortNum
		LOCAL i, lnModemPort
		lnModemPort = 0

		WITH THISFORM
		*~  Loop through the form array...
			FOR i = 1 TO ALEN(.aCommPorts,1)
				gnPortNum = i
				WAIT WINDOW [Testing COM ] + ;
					ALLT(STR(.aCommPorts(i,1))) + [...] NOWAIT NOCLEAR
				IF .ocxCOMM.PortOpen
					.ocxCOMM.PortOpen = .F.
				ENDIF
		*~       Open the port and send standard Hayes-compatible
		*~       commands to it. These commands first reset ([ATZ])
		*~       the modem if it's there, then tell it to return
		*~       an ID string ([ATI0]). The return string from a modem
		*~       will contain an [OK], which is how we can tell it's a modem.
				.ocxCOMM.CommPort = .aCommPorts(i,1)
				.ocxCOMM.PortOpen = .T.
				.ocxCOMM.OUTPUT = [ATZ] + CHR(13)
				.WaitForResponse(2)
				.ocxCOMM.OUTPUT = [ATI0] + CHR(13)
				.WaitForResponse(2)
				WAIT CLEAR
			ENDFOR
			WAIT WINDOW [Compiling Results...] NOWAIT NOCLEAR
			.timer1.ENABLED = .T.
		ENDWITH
	ENDPROC


	PROCEDURE timer1.Timer
		*~ Clear the variable used in the ONCOMM event
		*~ of the .OCX.
		RELE gnPortNum
		LOCAL i, lnModemPort
		lnModemPort = 0
		*~ Disable this timer so the code only runs once.
		THIS.ENABLED = .F.

		WITH THISFORM
		*~  Close the port if it is open.
			.ocxCOMM.PortOpen = .F.

		*~  Loop through the completed array.
		*~  If the first element is <> 0, 
		*~  check the second in the row for an "OK".
		*~  If present, that means the port has a modem.
			FOR i = 1 TO ALEN(.aCommPorts,1)
				IF .aCommPorts(i,1) <> 0
					IF [OK] $ UPPER(.aCommPorts(i,2))
		*~	            Modem found, exit the loop.
						lnModemPort = .aCommPorts(i,1)
						EXIT
					ENDIF
				ENDIF
			NEXT i
		ENDWITH

		*~ Report to user.
		WAIT CLEAR
		IF  lnModemPort <> 0
			MESSAGEBOX([Modem Found On COM ] + ALLT(STR(lnModemPort)),0,[])
		ELSE
			MESSAGEBOX([No Modem Found.] ,0,[])
		ENDIF
	ENDPROC


ENDDEFINE
*
*-- EndDefine: form1
**************************************************

DEFINE CLASS MSCOMM_OCX AS OLECONTROL
             OLECLASS = [MSCOMMLib.MSComm.1]
ENDDEFINE 

>How can I find out what comm ports are on a PC? I have a PC that doesn't have comm port 2 defined even though there is one on the PC. Any ideas?
>TIA!