Those plugs are most likely (hard to tell from a picture) Cisco console cable plugs.
They convert a DB-9 serial interface to a RJ45 receptacle , but NOT for use with a regular network cable. (They also exist in a DB-25 version.)
They are intended to use with a Cisco console cable (that has a RJ45 plug on 1 end and a DB-9 on the other) or a roll-over cable (RJ45 plug on both ends, but different pin-out than a network cable).
A Cisco console cable + a plug like yours connected to the other end make together a serial 3-wire null-modem cable.
A roll-over cable with 2 of these plugs (on each end) also makes a 3-wire null-modem cable.
That may be all you need. Provided that your lab-device needs a 3-wire null-modem cable, which is the most common case.
But some require a straight cable and in some (rare) cases you need a 5-wire null-modem (or straight) cable.
As modern computers, especially laptops, typically don't have a DB-9 serial port anymore, you may also need a USB to serial converter plug.
For short: There are a lot of variables here. Without more details about the devices involved and the exact nature of your plugs I can't get any more specific.
Answer from Tonny on Stack ExchangeCan you use an rj45 to rj45 rollover cable from the Cisco console port to a normal ethernet rj45 or do you ned a rj45 to serial adapter in a serial port for it to work
Pinout for serial cable with RJ45 on both sides?
Better DB-9 to RJ-45 solutions?
USB- Serial cable and an RJ-45 to Serial cable for connecting to the console por
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Those plugs are most likely (hard to tell from a picture) Cisco console cable plugs.
They convert a DB-9 serial interface to a RJ45 receptacle , but NOT for use with a regular network cable. (They also exist in a DB-25 version.)
They are intended to use with a Cisco console cable (that has a RJ45 plug on 1 end and a DB-9 on the other) or a roll-over cable (RJ45 plug on both ends, but different pin-out than a network cable).
A Cisco console cable + a plug like yours connected to the other end make together a serial 3-wire null-modem cable.
A roll-over cable with 2 of these plugs (on each end) also makes a 3-wire null-modem cable.
That may be all you need. Provided that your lab-device needs a 3-wire null-modem cable, which is the most common case.
But some require a straight cable and in some (rare) cases you need a 5-wire null-modem (or straight) cable.
As modern computers, especially laptops, typically don't have a DB-9 serial port anymore, you may also need a USB to serial converter plug.
For short: There are a lot of variables here. Without more details about the devices involved and the exact nature of your plugs I can't get any more specific.
As Tonny wrote, that adapter is most likely a Cisco RJ45-to-DB9 converter, which is a purely passive adapter. The RJ45 side is not Ethernet, it's just RS232 on a different type of connector (Cisco devices used to have console ports with an RJ45 connector rather than the more common DB9 or DB25 connectors).
If you have an RS232 port on your laptop, then you just need a cable. While this was extremely common a couple of decades ago, nowadays I believe it's quite rare to find a laptop with an RS232 port.
So what you need instead is more likely an RS232-to-USB (aka serial-to-USB) converter/adapter.
Once you have that, you should have a new character device for the serial port somewhere in /dev (details may vary, but probably some kind of /dev/tty-something).
If you just want to capture the data from the serial port to a file, you can just cat /dev/serial_port_device_name >filename.
If you need to change serial port settings you can use stty but beware that you must keep the port open while you do it, otherwise the settings will reverse to defaults right away.
If you want something more foolproof, you can probably write a short script using the language of your choice, or they may be additional tools to manage that.
Alternatively there are devices with serial ports and Ethernet connections (you would then usually use telnet or netcat to connect to the serial ports and capture the data), but these would be more expensive, and only useful if you need to capture data from a larger distance.
You're correct, standard ethernet cables won't work due to the wiring sequence - cisco uses what's called a "rollover cable" for their serial consoles. An example of the pin-out for rollover can be found here:
http://pinouts.ru/NetworkCables/rj45_rollover_pinout.shtml
It's as simple as pin 8 on one end is swapped to pin 1 on the other end, pin 7 to pin 2, etc. All the way down the cable.
If you have some Cat-5 cable, RJ-45 ends, a crimper, and the know-how to crimp your own cables - you can make your own rollovers fairly easily! If you don't wish to do that, I'd suggest searching for "Cisco RJ-45 Rollover" or similar in order to find vendors from which you can purchase RJ-45 to RJ-45 rollover cables.
P.S: Double-check the documentation of your KVM - some KVMs that allow serial management require their own proprietary adapters for it, even if the port on the KVM is RJ-45. If it does require a proprietary adapter, there's a chance that it will support standard RJ-45.
Haymaker beat me to it...
You don't say what Cisco device or what KVM, but chances are you want what Cisco calls a rollover cable:
Pin 1 on one end connects to Pin 8 on the other
Pin 2 Pin 7
Pin 3 Pin 6
Pin 4 Pin 5
etc.
Pin 8 Pin 1
This is basically a null-modem cable but with RJ connectors instead of DB. Here's a link to a different Cisco doc that describes console pinouts.
I have one single Cisco "ws-c2960-48tc-l v05" switch whits do not have a USB-mini-b console port
all the other Cisco equipment has a USB mini b console port and that's the only console cable I have
so can I just take an old cat5e ethernet cable and make it into a rj45 to rj45 rollover cable and plug it into a regular ethernet port on a laptop (and maybe download some driver) or am I better of buying a USB-A to rj45 console cable
We have a ThinkLogical Serial Console Server that I'm attempting to connect to some F5 Big IPs. Both devices have RJ45 jacks, and I'm trying to get them to talk to each other. The Big IPs came with TIA 568B to rollover adapters.
Connecting using RJ45 -> DB9 works just fine.
I've tried connections between the SCS and Big IPs with the following, in all permutations:
-
With and without the adapter. EDIT: Meaning with rollover and standard pinout ethernet cables.
-
DTE and DCE on the SCS.
-
Multiple baud rates on both sides.
Nothing has worked, so I can only conclude that the pinout is the problem. Does anyone know the correct pinout that I should be using? My google fu has failed me.
EDIT: Just in case someone finds this while searching for the same problem, here's the answer: my coworker accidentally used an F5 failover cable instead of standard ethernet. The failover cables have their own unique pinout, so they didn't work. The correct cable for this job is a standard rollover, or a standard ethernet cable with a rollover adapter (which is included with the Big IPs).
We also had to change our serial console server from DCE to DTE, turn off all flow control, and (obviously) match baud rates and parity on both sides. The Big IPs default is 19200 8N1.
Probably like many, I've got a stack of these DIY DB-9 to RJ-45 adapters for console access because every manufacturer is special and needs their own unique pinout to accomplish basic serial communication.... Worked well enough with my Toughbook CF-19, but need another serial extension cable to fit in the flush DB-9 ports on things like my Dell Latitude Rugged laptop and CF-20 tablet.
Cleaning/reorganizing my tool bag today, looking at these things, and curious if there's a better mousetrap out there? I know could just pick up a generic premolded RJ45 female to DB-9 adapter, then make custom CAT5 cables to match, but that would take up a lot more room in the tool bag too.
Would be great if someone made something similar to these custom adapters but with a molded DB-9 end, or maybe something like a RJ-45 coupler that could be repinned, so I wouldn't have to carry a bunch of bulky cables.
I wasn't sure if ccent and/or ccna would have been a better place to answer this, I wanted to try here, first. I am familiar with a rolled cable, but I have always used the cable that comes with the equipment. I know that they are not compatible between vendors, for example, my HP console cable doesn't work when connected to a sonicwall. I have not cross tested each manufacturer, so there is no need to say that HP works with x, etc...
My question is specifically for cisco devices. If I create my own rolled cable (hypothetical situation, I know you can get them cheap and I have a handful already) can I use any type of rj-45 to serial adapter or is the pinout on the adapter not always what it needs to be (hopefully that makes sense)?
Let's say I bought this, would it work or are the pins not in the correct order from the rj-45 to serial portion? I know some of these devices come apart and you can set the pins however you want, but is there a specific order for the 232 side?
https://www.amazon.com/Tripp-Lite-Modular-Adapter-P450-000/dp/B0029L0V48/ref=sr_1_7?ie=UTF8&qid=1477754001&sr=8-7&keywords=rj45+to+serial
Thanks.