Connecting to serial port with adapters question

K

Kettchxxii

Gawd
Joined
Jun 13, 2007
Messages
651
So I need a serial connection to communicate with my 'new' powerconnect switch. My primary PCs do not have serial ports currently, although looking at my manual I see I do have one internally. Looks like monoprice has Serial to Ethernet cables for 65 cents each.

Would a USB to Serial connector work for the connection that I will need to access the switch or should I hunt down a bracket for my internal COM1 port and use that?

Either PC -> USB -> Serial -> RJ-45 -> Serial -> Switch

Or [find or buy the damn internal cable] Serial to RJ45 to Serial.

Anyone sitting on a internal header COM1 to external DB9 bracket?
 
I have never use seiral to ethernet so i'm not sure

I do use serial to USB and they work fine
 
Do you have a Yost cable running around? Usually light blue and usually thrown away by people when they open the box of a configurable/managable component. You can also usually pick up a serial to ethernet adapter at most Radio Shacks or computer shops. I have 3 onthe shelf right now. I usually use web access for my managable switches via laptop and it at first. Then once configured I put it on the LAN. I have even begun to access my managable devices via remote web access and it helps a lot with menial config tasks.
 
The switch was shipped with just the power cable.

I am new to all of the special cables that accompany this sort of thing.

Looks like I can just buy a internal com1 to external serial cable for 5 bucks off ebay, use those 65 cent serial to cat5 cables and use my existing cat5 I have laying around.

Would the cat5 cable need to be wired any special way?
 
I would first try USB to serial. If you used the DB9 to RJ45 adapter, you have to see the pinout that the Dell requires. Since I have a serial port on my laptop, I just use a straight through serial cable.
 
If by serial to ethernet you mean the Cisco style console cables it's actually just rollover with a specific pinout. If you look around for DB9 to RJ45 Cisco Console pinout you should find that info.
 
FYI, there are two different adapters for connecting the internal COM1 header to an external DB9 port. Intel previously used their own pattern, while pretty much everyone else used a different pattern. I don't remember exactly what the difference was, but it was something like

1 2
3 4
5 6
7 8
9

vs.

1 6
2 7
3 8
4 9
5

You just need to make sure that the adapter you use matches up with the pattern on your mobo. Usually the board will come with the adapter for it.

Also, the USB-serial adapters can sometimes be quirky. A lot of people reported problems using them for engine monitoring via a car's ECM. Certain ones worked ok while others didn't work at all. It seems to have been based on which chip was used in the converter and the bitrate it ran at. I know we use the USB-serial adapters at work for our Cisco gear, but just keep in mind that some adapters could possibly be the cause if you run into weirdness.
 
I've never had a problem running standard RS-232 serial with the cheapest USB adapters I can find. Most of the problems I've heard of are people trying to do weird stuff with them, like program microcontrollers (tight timing requirements), run MIDI (weird bitrate), use the control pins as interrupt sources and so on. For standard management purposes I've never had a problem.

Also those 'Serial->Ethernet' adapters ... aren't. They just put the serial data pins on an RJ45 connector so you can run Cat5 patch cables to carry your serial. You can't plug them into an Ethernet network and expect it to work (such devices do exist, but they're in the ~$100+/port range). I use SKU 24512 @ DX fairly extensively. Uses the pl2303 chipset, well supported under Linux, but be prepared for running unsigned drivers if you need it to work on Windows.
 
I had wonky issues going usb-serial. Had to get an actual card with the DB9 rs-232 connector on it. I guess you won't know till you try.
 
I went ahead and ordered a serial cable, a null modem serial cable, and two of those serial to rj45 connectors. We will throw everything at the wall and see what sticks. Ill report back what happens 0.o
 
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