Null Modem Cable?

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Null Modem Cable?

Postby emc2 » Wed Jun 25, 2008 5:48 am

I have the microstamp11 "MAX" product.

My product came with a serial cable but it does not look like a null modem cable. (None of the pins are crossed over).

I can get the demo program to work easily.

HOWEVER, I cannot get ANY other serial communications program, including the image craft hello.c program to display information in the hyperterminal.

I have come accross an article which shows a null cable connecting the pc to the microstamp.

Should I be using the serial cable that came with my starter kit or should I be using a null modem cable for serial communications?

thanks in advance
emc2
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I am wrong about the null modem cable

Postby emc2 » Thu Jun 26, 2008 12:13 pm

I dont understand why they use a null modem cable in this online circuits lab...
Your personal computer communicates with the μStamp11 through its serial port. The human user communicates
with the serial port through a terminal program such as HYPERTERMINAL.You can open HYPERTERMINAL
in WINDOWS by following the path START -¿ PROGRAMS-¿ACCESSORIES-¿COMMUNICATIONS-
¿HYPERTERMINAL. You can identify the serial port on the back of your PC by its distinctive 9-pin
D-shaped connector (a so-called DB9 connector). There should be a null modem cable connected to this
connector.
The other end of that cable will be connected to the μStamp11’s docking module. The connection
between the μStamp11, the breadboard, and the personal computer is shown in figure 4. In your lab kit


The docking module is acting as a DCE which means it is transmitting on line 2 and receiving on line 3. The terminal on your PC is acting as a DTE which means it is receiving on line 2 and transmitting on line 3. So it is a DTE->DCE communicaton and a straight serial cable is what is needed.
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Postby cbarnes » Mon Mar 16, 2009 5:20 pm

They are wrong-- it should not be a Null Modem cable.

Carl
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