Serial Console Extension doesn't work, and appears to have wrong pinout

[ggiesen]

Disclaimer

• I have read and understood the disclaimer.

Application version

0.4.9

System version

0.2.7

Device model

JetKVM

Extension model

Serial Console

Remote device Hardware

Cisco ASR1001-X

Remote device OS

No response

Bug description

Still having issues from the closed issue #267.

I've reached out to support via email twice (no response over 2 months) and reached out on Discord here, but have still not come to a resolution.

I'm trying to use the Serial Console Extension with a bog-standard Cisco DE-9 > RJ45 rollover cable. Tried the null modem adapter per #267 as well. With the null modem adapter, I can get output from the router, but no input.

I checked continuity from various pins on the SP3232E to the DE-9 connector:

SP3232E Pin 10 (T2 IN) > DE-9 Pin 5 (GND)
SP3232E Pin 11 (T1 IN) > DE-9 Pin 2 (RXD)
SP3232E Pin 12 (R1 OUT) > DE-9 Pin 3 (TXD)

(RXD and TXD flipped if using null modem adapter)

I also checked continuity on the RJ12 side:

SP3232E Pin 14 (T1 OUT) > RJ12 Pin 3
SP3232E Pin 13 (R1 IN) > RJ12 Pin 2

I'm not an EE, and this is not my area of expertise, but it would seem to me those pinouts are incorrect.

Here's the pinout for the SP3232E:

And here's a picture of it on the Serial Console extender board:

Here's the datasheet for the SP3232E:

https://www.maxlinear.com/ds/sp3222e_sp3232e.pdf

This seems really weird to me, as I would have expected the pins facing the DE-9 connector to be on the RS-232 pins (T1OUT, T2OUT, R1IN, R2IN), and not the TTL-level logic pins (T1IN, T2IN, R1OUT, R2OUT). I also find it really weird that T2IN is connected to ground.

It's almost as if someone mirrored the pin config, or substituted a different chip than the original layout and didn't update the layout.

Has anyone been successful in having support address the issue?

[dseven]

I know you're frustrated about lack of progress on this, but I just looked at it again, and since there are people successfully using the serial extension, I have to ask... are you certain that you read the pins on the chip in the correct order? Everything (else) makes sense about your continuity test results if you just reverse the order of pins 11 thru 15...

I assume the Cisco router/cable works as expected when connected to a PC?

If so, perhaps you have a defective chip on the extension board, RJ12 cable, or maybe even the JetKVM itself. Do you have any other extensions to try (to validate the JetKVM and RJ12 cable)?

Another thing you could try would be to short the TXD and RXD pins together. With that in place, anything you type in the extension console should be echoed back to you. You could try this on both the RS232 side of the extension and the RJ12 port on the JetKVM (one at a time, of course!).