Serial extension with Cisco serial cable

[joelaulk]

I cannot get any input or output when connect the serial extension to a Cisco console cable.

Example this is the cable I'm using, and it has been tested working on a PC serial port.
https://www.cable-tester.com/rj45-rs232-console-cable-pin-out/

I have tried different browsers Firefox and Chrome, both same result cannot see any input or output.

Kindly advise how to troubleshoot this.

[akhepcat]

IIRC cisco console cable is a roll-over, so swaps TX and RX for you.

You might need a null-modem adapter in the middle

[joelaulk]

Any idea what is the pinout diagram for this serial extension box ?
Is it different from a PC serial port ?
Doesn't look like it's published anywhere.
Would like to make a comparison before buying random parts from China.

[Vivid-Reality]

I'm in the same boat; I can not get the Cisco console to respond to the serial module. The Cisco console cable (rollover cable) is designed to connect a standard RS-232 serial port. We shouldn't need "unroll" it.

[joelaulk]

I have sent support a email asking about getting the pinout diagram for this serial extension.

[xudaaaaa]

I have the same issue here.

1. Using ketkvm serial extension with RJ45 to DB9 (female) line connect to my Cisco and Huawei switch, nothing happened on web ui.
2. To verify if it's the RJ45 to DB9 (female) cable issue, I connect it directly to my PC ( and there is another USB to DB9 male ) cable, it works well.

[shinygecko]

Just noticed the same issue, any workarounds?

[joelaulk]

Can everyone log a case with support@jetkvm.com
It's time to start flooding them with support emails.

Since I started this thread it still got no where. Radio silence from support as well.

If someone has a null modem adapter can you try it as well and feedback here.

I'm actually suspecting does the GUI console works at all, but doesn't have the skills to troubleshoot browser/HTML stuff.

I hope this product doesn't sell on Amazon. Support is not ready for this.

[shinygecko]

I picked up the following adapter and it worked for me for a standard Cisco console connection.

https://www.amazon.com/dp/B075XHWVSJ?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1

[joelaulk]

I picked up the following adapter and it worked for me for a standard Cisco console connection.

https://www.amazon.com/dp/B075XHWVSJ?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1

Great I'm glad a null modem adapter has worked. You have already done more that what Support can provide.

I'm off to get a pair of null modem adapter to test this.

[benumbed]

Please don't promote hammering JetKVM's small staff. This product blew up far more than they expected and they're still dealing with the surge. Give them some time to catch up :). If they hadn't open-sourced most of the firmware I'd be less sympathetic, but they did, and there is a growing community around these devices that's been pretty good at figuring issues out (as demonstrated above)!

That said I'm now off to go build a null modem cable to see if I can get my serial console to cooperate 😁.

[joelaulk]

If they want to commercialize this product they need to hire more people.
A pinout diagram is so difficult for them. Still no reply after 1 month.

A lot of us just want to use the product as it is, not interested in software development.
Using Github as a issue tracker i don't know to laugh or to cry.

That said I'm now off to go build a null modem cable to see if I can get my serial console to cooperate 😁.

If you have time to build something, might as well build a extension port RJ12 to serial console RJ45, without going via this time wasting serial extension module. Someone in Discord has done it.

I can also confirm a null modem adapter fixed this issue.

[xudaaaaa]

Thanks everyone, I bought a null modem ( https://detail.tmall.com/item.htm?id=610662724483 ) and confirmed that it does work for me, and as a replacement for Amazon.

But I am confused, since jetkvm is here to control network devices, it should integrate the correct pin definition into the extension instead of requiring the end user to buy a separate patch.

And the whole thing is not as elegant as I expected. Now I have a RJj11 cable - Serial integration - NULL MODEM - DB9 - RJ45 cable on my desk, and finally to my network device. And the whole thing is still not updated in the documentation.

Serial Console
Direct access to the device's serial console for diagnostics and low-level control. Unlike the other extensions, that ship with the JetKVM device, this extension will ship separately. We're actively developing it, but a 3D render is not yet available.

Anyway, still love this little stuff and hope this community better.

[xudaaaaa]

@joelaulk

If you have time to build something, might as well build a extension port RJ12 to serial console RJ45, without going via this time wasting serial extension module. Someone in Discord has done it.

Could you please share more information about the self-build cable so I can have a try if this works ? Just a cable would be more beautiful for whole thing. I tried search on Discord but didn't find it.

I was thinking build a RJ11 to RJ45 cable so directly connect Jetkvm to network device, but ChatGPT told me not to do so since the RS-232(network device) nad UART(jetkvm) has different voltage levels.

I opened the expansion and found that there is indeed a chip like MAX232 inside. And I asked myself: "Why did they sell me a $15 extension if just one RJ11-RJ45(with correct pinout) cable would solve the problem ? " so I give up this thought.

[TorranceTM]

Here is the more info on the self-built cable - #101