Null Modem vs RS232

[DanGlee]

Hi,

I have a quick question regarding connecting my 800HD to my PC!

I originally tried to flash it via OTA ip address, but for whatever reason it failed and now I'm getting "ERR01: NO CA FOUND"

I have been trying to get hold of a cable and the best I could get so far is a USB => RS232 (Female)

I assumed this would work. I have tried connecting this via DreamUp and using the drivers that came with the cable, its defo pointing to COM3 but nothing is happening.

I was browsing the web and found a link that said this:

"Required
Null Modem Cable (this is NOT the same as a serial or rs232 cable, although it looks the same)"
via:
_http://www.digital-kaos.co.uk/forums/f34/guide-flashing-dreambox-dreamup-33/

Anyway, to cut a long story short...

Does it DEFINITELY have to be a null modem? (I thought the RS232 was a null modem?)

and, importantly... does the null modem have to be the same on each end, or can it be USB => Null Modem? Because I don't have the RS232 / Serial connection on my PC, as most new PCs don't any more?

Any help / advice much appreciated!

Thanks,
DG.

 

[PaulR]

They both use the same cable and ends (although there are 9 pin and 25 pin variants on both) but the null modem cable has the transmit and receive cables cross linked from one end to the other rather than straight through.

See _http://en.wikipedia.org/wiki/Null_modem for further information.

If needs a null modem cable and it's not a null modem cable then it won't work.

If you haven't got a serial port on your computer then that's a different kettle of fish. There are USB to serial adaptors but they are a bit tricky to set up I believe.

PS Please put an underscore before any links

 

[DanGlee]

Hmmm...

Thanks for the reply!

Looks like I could be stuck then? I only have USB on my PC so i need to figure out how to get it to my PC to connect as its €250 sitting here with an error screen!

Does anybody have any ideas? I am assuming somebody must have done this before because most people would have new PCs that are doing this?

Please Help!

 

[compufunk]

I've recently used a noname USB to serial adapter to flash a a new image to a box. I had no problems, but I've read some people have trouble with them. I couldnt find drivers for Vista, but it worked fine on XP.

Does it DEFINITELY have to be a null modem? (I thought the RS232 was a null modem?)

Yes, a null modem cable is required. Serial RS232 is of no use to you.

A null modem cable should be easy to identify. It has female connectors at each end. A serial RS232 cable has male at one end and female at the other.

_http://en.wikipedia.org/wiki/Null_modem

Set the attached images, the first one is a null modem cable, the second has a male connector at one end and is a regular serial RS232.

 

[DanGlee]

But how do I connect a null modem to my PC? I don't have that connection on it?

 

[DanGlee]

The cable I have is a mis-match!

Its a USB to RS232 (Male) but with a Female converter adapter on it!

 

[PaulR]

It's possible the male to female adaptor is itself a null modem adaptor. Are there any markings on it? There's a picture at the top of the Wikipedia article.

 

[DanGlee]

No, there are no marking. Its not like the picure.

I checked, it, it just says "gender changer"

 

[DanGlee]

Just a thought?

But is it possible to connect to it via a network cable?

Oh and what's the point of the USB cables? Can't we use them to update?

 

[compufunk]

But how do I connect a null modem to my PC? I don't have that connection on it?

Use a serial to USB Adaptor.

Just a thought?

But is it possible to connect to it via a network cable?

Yes you could, but your original post mentioned that flashing over the network was failing, hence the requirement for a null modem cable

Oh and what's the point of the USB cables? Can't we use them to update?

What USB cables? Unfortunately, you cant flash over USB.

If you are comfortable with fiddling with wires, you could rewire the RS232 so that its effectively a null modem cable. I use two serial cables spliced together and it works a charm.

 

[Huevos]

Mate, if you have a USB/RS232 converter cable you also need a null modem cable. Plug the USB end of USB/RS232 converter cable into the PC. Plug the null modem cable into the other end of the USB/RS232 converter cable. Plug the other end of the null modem into the receiver. This is the same for all receivers that have an RS232 socket, not just Linux boxes.

 

[DanGlee]

Mate, if you have a USB/RS232 converter cable you also need a null modem cable. Plug the USB end of USB/RS232 converter cable into the PC. Plug the null modem cable into the other end of the USB/RS232 converter cable. Plug the other end of the null modem into the receiver. This is the same for all receivers that have an RS232 socket, not just Linux boxes.

Ahhh... thats the job. Just ordered a "proper" female null modem from ebay for about 50p... so when that arrives I can still use the USB/RS232...

Thanks...

I'll keep you posted on how I get on!

thanks
DG

 

[DanGlee]

Us a serial to USB Adaptor.

Yes you could, but your original post mentioned that flashing over the network was failing, hence the requirement for a null modem cable

What USB cables? Unfortunately, you cant flash over USB.

If you are comfortable with fiddling with wires, you could rewire the RS232 so that its effectively a null modem cable. I use two serial cables spliced together and it works a charm.

Thanks for the reply.

Oh and I meant USB connectors.

It does seem strange you can flash via USB? Oh well...

Thanks again!

DG.

 

[DanGlee]

UPDATE:

My null modem cable arrived today. Connected it to PC via the USB>RS232 connector originally bought and its working! (Kinda)

Need to get the "Flash" button to ungrey... !

 

[DanGlee]

One more quick question if anybody reading...


I have the DreamUp working with the cable and I'm uploading Enigma2, but was wondering is it just me or does it normally take 600+ minutes (about 9 hours!) to upload a 35mb file?

Thanks.

 

[compufunk]

It takes longer using the serial cable than it would over the network, but only around 30mins or there abouts.

Something is wrong with your setup if its taking that long.

 

[DanGlee]

I thought it was to slow!

I says uploading 0 kb/s but the green bar is moving along (albeit, slowly!)

I dunno if I should stop it or not? Will it **** more?

 

[DanGlee]

NB:

Would it matter that I'm going through the null modem, to an RS232 to USB converter?

(I'm running it on a Dell XPS, USB2.0 so it should be no problems there!)

 

[vantanevn]

you check your null cable. it't connect the pin 2-3, 3-2, 5-5