TROUBLE SHOOTING YOUR EXTERNAL SERIAL PORTS WITH A
RS-232 MINI TESTER
RADIO SHACK 276-1401 OR EQUIVALENT

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If you've tried just about everything ELSE and still can't get your computer to "talk to the radio", then these units permit a visual approach to analyzing data flow on your serial port, and will save you literally hours of frustrating 'work'..

The Radio Shack unit has ONE LED per line,
and has a MULTI COLOR function
Green is HIGH - Red is LOW

TWO LEDS PER LINE testers WORK the” same”,
Except that the two LED's colors are reversed.
Green is LOW - Red is HIGH

Hint

These pictures are 'shrunk' to fit the browser screen,
but They are really much larger!
RIGHT CLICK on the above Graphics files
Choose ''Save Image'' to download to your computer.
Choose ''View Image'' to see it FULL sized .

Connect this device BETWEEN the RS232 Interface and your computer. (IN LINE)

EACH UNIT “LOOKS AT” SEVERAL LINES, The most important ones are listed below:

TD		Transmit Data from computer to RADIO
RD		Receive Data from RADIO to computer
RTS		Ready to Send 
CTS		Clear to Send
DSR		Data Set Ready
DCD		Data Carrier Detect
DTR		Data Terminal Ready



AT MAIN MENU (Not Scanning)

IF your commport is correct:

“X” means “usually the case ”, but not “always” 


. DTR should be LOW	
. CTS should be LOW	X
. RTS should be LOW	X
. TD should be LOW		X
. RD should be LOW

AT SCANNING MODULE (While Scanning) 
. DTR should be HIGH	ALWAYS  HIGH or self powered interfaces will not get power (won’t work)
. CTS			Flickers between red and green OR stays HIGH
. RTS 			Flickers between red and green OR stays HIGH
. TD HIGH		Should FLICKER, but only HIGH when data flowing (scanning)
. RD should be LOW	Depends, but with AR8000 and most modern radios, 
	 		   Flickers HIGH  but with ‘delayed sync’ with TD

IF you are scanning, mainly TD and RD will flicker so fast they appear as one color (HIGH), BUT, if you click on pause, while the ‘rate of flow’ changes to about 2 times a second, the signal strength ‘polling’ should show activity. RETURNING to main menu should then again show settings as above. IF the DTR does not change status, this ESPECIALLY means the wrong comm port is chosen OR Windows is using it for some other ‘device’. You will have to resolve THAT issue before progressing further.

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