IC problem

[badai]

I have serial cable consist of 4 ports(on pcb).........one of them cannot work(physical problem). My expectation is because of the IC on that port. So, how i can know this is because of IC problem? Is it enough to test it using multimeter and compare with other IC from different port??? Any idea

 

[MP1]

You have data bits on this line, which are just pulses. Use a scope or other device that will allow you to watch the pulse stream and compare with the other ports. By working your way through the circuit, you will be able to find the place where the signal stops.

MP

 

[prateeksikka]

i feel that u dont even need a scope!!.
u can perform continuity test using a multimeter only...

 

[MP1]

You cannot measure continuity through the RS232 driver circuit. You will need to follow the pulse stream and see where it ends.

MP

 

[Theatronics]

When you say the port is on a PCB and connected to a 'Chip'
Is this perhaps a UART or a Driver chip?
For smaller projects I like the MAX232.

I have had a lot of luck with an inexpensive logic probe.
It shows 2 LEDs (Red=High, Green=Low) It is easy to follow
a serial signal through a circuit just with that tool.

I the device connects to a terminal of any kind, is it possiable to
remove the driver chip/Uart from a socket and jumper the TX and RX signals
to create a Loopback test.  This will confirm that the problem is NOT in the circuitry leading up to the IC.

Send more details, This should be easy to hunt down. 

-Mike