Null cable question

[IBHomer]

My laptop doesn't have a serial port, only USB 2.0. I purchased a USB to Serial adapter cable to connect with my receiver. Do I also need a null modem adapter or will the USB port configure pins 2 & 3 automatically?

 

[Mr Tony]

the cable must be either a null modem cable or you have to add an adapter to make it work right

 

[PSB]

I just got a USB to RS232 from Sadoun, I use a null modem cable with it for up-downloading to my Traxis DBS 3500

 

[Vacosta]

Maybe a dumb question, but if I have a modem cable that has a 9 pin RS232 (female) and parallel connection (male) will that work? The bag it came in says "Modem Cable" but doesn't make reference to Null.

 

[Mr Tony]

no. Thats a straight through cable

Null modem will say "null modem" on the cable itself. You can add an adapter (Radio SHack carries them for like 5 bucks) that you can add. Thats what I have as one reicever needs a null modem and one doesn't

 

[Mr Tony]

Maybe a dumb question,

There are no dumb questions

 

[Vacosta]

Appreciate the quick reply. So do some receivers use a straight modem cable and others null? How would you know which use which?

 

[PSB]

Should say in the manual, best to have one of each anyway! One to Download/upload

And one for cloning receivers

RS232CL null modem cable
male to male connectors


RS232PC serial cable
male to female connectors
used for PC to receiver loading

 

[Vacosta]

Now we may have opened up a can of worms PSB but since you are the pro at directing people to previous posts with pertinent info, can you let me know if this discussion has been brought up before? That way I'm not asking too many questions. I guess I could just do a Forum Search, but if you remember any good posts, let me know. THX!

 

[PSB]

Here is a good one.......

http://www.satelliteguys.us/showthread.php?t=16344&highlight=rs232+cable

 

[IBHomer]

Thanks for all the quick replies. My ViewSat Extreme says to use a null modem cable to connect from PC to receiver. I found a gender bender and a null adapter that I'll try first to see if the PC "sees" the com port assignment from the adapter cable. I don't want to "fry" my new receiver. The serial plug on the back is male and my USB to serial adapter is also male requiring the gender change. So what I have to do is plug the null adapter on the receiver and then the gender changer and finally the USB to serial cable. Hope it all works!!!!

 

[SatelliteAV]

You won't fry your receiver or the PC if mismatching a straight thru or a null RS232 cable. The computer and the receiver simply will not communicate.

 

[IBHomer]

Using "Loader2" to upload sat info won't work. Seems like it tries to start but can't initialize and keeps retrying. Is my cable setup probably at fault? Windows sees the COM port as COM7 on one USB port and COM6 on the other. I set that in "Loader2", tried both, same result. Changed baud to 9600, no good. Any help, please?

 

[Mr Tony]

You won't fry your receiver or the PC if mismatching a straight thru or a null RS232 cable. The computer and the receiver simply will not communicate.

so true. I keep forgetting which recever needs the null and which doesn't. If I hit "start" and it doesn't do anything, then I have the wrong cable

 

[mdonnelly]

All the USB-to-Serial adapters are for is to give the PC a DB9-M connector and a virtual serial port number, and make it a DTE device.

If you want to attach that directly to a terminal (or another DTE device), you'll need a null-modem adapter or cable in between.

If you want to connect to a modem (DCE device), you'll use a straight through cable.

 

[SatelliteAV]

Using "Loader2" to upload sat info won't work. Seems like it tries to start but can't initialize and keeps retrying. Is my cable setup probably at fault? Windows sees the COM port as COM7 on one USB port and COM6 on the other. I set that in "Loader2", tried both, same result. Changed baud to 9600, no good. Any help, please?

Sounds like a bad serial connection.

Check the cable with and ohm meter and verify that pins 2 and 3 are crossed ... I.E. pin 2 on one end of the cable is crossed and connected to pin3 on the opposite end of the cable.