Null Modem Cable

[oracle00]

I have been told that if a 9-pin cable has female ends at both end, it is confirmed a null modem cable and not a serial cable... is that true?

thanks in advance!

[commach]

Not true.....

[oracle00]

thanks for the quick reply... guess i have been duped in buying the wrong cable... somemore i was reconfirming this with the shop owner as the label package outside indicated it as a serial cable... but the shop owner said both end female means null modem....

[ceecookie]

Ouch. Next time be more careful :(

[oracle00]

i was careful... just tat i was ignorant :o:o:o

[commach]

thanks for the quick reply... guess i have been duped in buying the wrong cable... somemore i was reconfirming this with the shop owner as the label package outside indicated it as a serial cable... but the shop owner said both end female means null modem....

I DIY countless serial cables for connecting CNC machine to the RS232 port of computer using 2 x D9 female connector as cable extension or connect to data switch/selector box.

But don't jump into conclusion yet, the cable you bought could be use as null modem cable depends on how the pins are being connected. Your best bet is to try using it with 2 computer connecting both RS232 ports together and run the null modem test.

Some people call a null modem cable as crossover cable, so the one you are holding might be a null modem cable.

[oracle00]

I DIY countless serial cables for connecting CNC machine to the RS232 port of computer using 2 x D9 female connector as cable extension or connect to data switch/selector box.

But don't jump into conclusion yet, the cable you bought could be use as null modem cable depends on how the pins are being connected. Your best bet is to try using it with 2 computer connecting both RS232 ports together and run the null modem test.

Some people call a null modem cable as crossover cable, so the one you are holding might be a null modem cable.

i connected the cable which i bought from my pc to another device so as to flash the device.. but the program cant detect that device... that's the reason why i asked the question cos i am thinking whether the problem is with the cable or lies somewhere else..

from googling, i understand that the null modem cable is wired slightly differently from a serial cable... supposedly a multimeter can be used to test if the cable is a null or serial cable... but i dont have a multimeter... and from what i see on the net, most serial cables seems to have 1 male and 1 female... so i was inclined to think maybe the shop owner is right... but from your advice earlier, this seem not to be case....

i will see if i can return the cable tomorrow... :(

[commach]

Wait a minute, when you connect the cable to another device, did you disable installed firewall?

[commach]

Apart from the firewall, i hope you are aware of the setting of the 2 RS232 ports, both need to be configured with the same setting of stopbit, baudrate etc.... if both ports are not using the same setting, likely the application will not be able to detect the device.

[oracle00]

Wait a minute, when you connect the cable to another device, did you disable installed firewall?

just tried that upon reading your post... no response too...

[oracle00]

Apart from the firewall, i hope you are aware of the setting of the 2 RS232 ports, both need to be configured with the same setting of stopbit, baudrate etc.... if both ports are not using the same setting, likely the application will not be able to detect the device.

i cant really change the settings for the device.. based on the manual it says "Bitrate 115,2 kBit/s max."

my comp settings for com1 is:

Bits per second: 9600
Data bits: 8
Parity: None
Stop bits: 1
Flow Control: None

i assume that should be ok?

[oracle00]

commach, do you know of any shops in simlim that sells null modem cable? many thanks for your help on this matter...

[xinus84]

or, get an adapter. from female-to-male.

[commach]

commach, do you know of any shops in simlim that sells null modem cable? many thanks for your help on this matter...

I never buy null modem cable from shops in SLS, usually i DIY the cable because from experiences, those shops are not very familiar with null modem cable, most of them can't tell which is null modem cable, serial data cable or serial extension cable, if you were to ask them which pins to connect for null modem cable, they will O.O..... forget it.

I suggest you ask a shop in SLS 5th floor to solder one for you or buy one from them, the shop is call Meico Lotus. they are pro in soldering all type of customize cable hence you can hardly go wrong getting null modem cable from them.
This shop is at one of the back lane which sell many peripheral with tons of cables laying around or placed on the shelves.

http://www.simlimsquare.com.sg/stores_floor/l6?page=1

[commach]

or, get an adapter. from female-to-male.

Changing the gender won't change the internal connection of the pin 2 -3 and 3 -2 cross connection.:)

[oracle00]

I never buy null modem cable from shops in SLS, usually i DIY the cable because from experiences, those shops are not very familiar with null modem cable, most of them can't tell which is null modem cable, serial data cable or serial extension cable, if you were to ask them which pins to connect for null modem cable, they will O.O..... forget it.

I suggest you ask a shop in SLS 5th floor to solder one for you or buy one from them, the shop is call Meico Lotus. they are pro in soldering all type of customize cable hence you can hardly go wrong getting null modem cable from them.
This shop is at one of the back lane which sell many peripheral with tons of cables laying around or placed on the shelves.

http://www.simlimsquare.com.sg/stores_floor/l6?page=1

hi, many thanks.. will check out meico lotus...