PDA

View Full Version : Serial com how to assure it is working properly?


zillah
Jan 5, 2007, 07:22 AM
I have got new laptop Dell Latitude D620 with win2003 OS SP1 all updates installed.

I have been experiencing a problem: when I used two emulators : HyperTerminal or SecureCRT, I can not connect to Cisco devices ( not only one device,, that means there is no possibility that a device is defected) .

There is no problem with a cable that connects my PC to a Cisco device, because the same cable with another PC is working fine.

There is no problem with windows OS 2003, because when I installed the fresh copy of 2003, the same problem is still going on!!

I have been advised that might be the problem with serial com port.

How can I verify (assure) that com port is working properly, and the problem with something else ?

I have checked BOIS, com enabled

And you can the Figure of device manager in the link below as well:
http://img243.imageshack.us/img243/8396/co...yworkingfm4.jpg (http://img243.imageshack.us/img243/8396/com1verifyworkingfm4.jpg)

http://img243.imageshack.us/img243/8396/com1verifyworkingfm4.th.jpg (http://img243.imageshack.us/my.php?image=com1verifyworkingfm4.jpg)
Any other suggestions ? Do I need to do some test ?

Thanks

Peter Kwan
Jan 6, 2007, 07:59 AM
To test your serial com port, bring up your HyperTerminal, connect to that com port, usually COM1, connect a DB9 (I assume is a DB9) connector to the com port with the RX (receive pin 2) and TX (transmit pin 3) shorted, just to make sure, short RTS (pin 7) and CTS (pin 8) as well.

Once you have done that, try to type any character on the HyperTerminal, you should see whatever you type, it echo back twice, one from your typing, one from the echo from short of the com port.

If you see double character for whatever you type, your com port is working, else the com port is bad or driver problem.

zillah
Jan 6, 2007, 10:22 AM
What basically I did , I attached serial dial up modem to the laptop's com, and I installed the modem , it was installed successfully without any problem , and I run the modem diagnostic test, it was OK.

zillah
Jan 6, 2007, 10:58 AM
it echo back twice,
I could not see echo when I tried this :
Serial Port Test from Hyperterminal - Support - National Instruments (http://www.ni.com/support/serial/verhyper.htm)

Peter Kwan
Jan 6, 2007, 02:21 PM
Your COM port is working, it seems like is your com port configuration, try to configure your com port to 9600bps, Data bits to 8, parity None, 1 Stop bit, and the flow control to Xon and Xoff. Is RTS and CTS shorted on your cable?

Let me know if this works.

zillah
Jan 6, 2007, 09:44 PM
and the flow control to Xon and Xoff.
The default value is: No,, do we want to change that to permanent or for tesing purposes ?


is RTS and CTS shorted on your cable?
I just want to clarify little bit, right nw I have got readymade cable (rollover or console cable), do you want me to make a cable ?

Thanks

Peter Kwan
Jan 7, 2007, 07:28 AM
Do NOT alter the original cable that came with the Cisco device, here is a link to explain a difference type of RS232 cables.

RS232 serial null modem cable wiring and tutorial (http://www.lammertbies.nl/comm/info/RS-232_null_modem.html#intr)

You mention that on your original post “There is no problem with a cable that connects my PC to a Cisco device, because the same cable with another PC is working fine.”

Can you find out what the port configuration on the working PC and compare it with the Non working PC. And change accordingly.

I am assuming that you are still using the same cable, Changing the flow-control is just enabling the handshaking signal.

Just curious, with is this Cisco device?

zillah
Jan 7, 2007, 09:41 AM
Can you find out what the port configuration on the working PC and compare it with the Non working PC. And change accordingly.
Same mine exactly.

I tried now to use my laptop , it worked, I do not why!! I think there is something causing this problem