In an attempt to make my network rack as easy to manage as possible, I am looking to connect the serial port of my PowerVault MD1420 to my DMPU108E KVM.

Currently, I can connect the USB mini port of the MD1420 EMM to my laptop, and I can initiate a serial connection through Putty. I also have a MPUIQ-SRL module for serial connections to the KVM. As seen in the linked doc, the serial module has an RJ45 jack that is detachable from the RS-232 plug.

My question is, for the purposes of a serial connection, is it possible to wire a USB mini port to an RJ45 jack, or are there additional ICs needed to convert this? Is it as simple as transposing a pin out diagram such as this for USB to serial, and this for serial to RJ45 (thus wiring the USB directly to RJ45)?


1 Answer 1


The first module that you showed with the USB-A plug on one end and the DB-9 connector on the other end has a USB to serial converter chip in it and may also have a separate logic voltage level shifter to the +/- voltage swings expected on RS232 signals. (Actually unknown if this device has a single chip capable of both functions or not).

The second linked device is a simple converter / wiring adapter that translates a RS232 connection on a DB-9 connector over to an RJ45 connector to be able to deploy a more convenient type of interconnection cabling.

You cannot simply connect the four pins of a USB-A connector to an RJ45 connector and expect that the RJ45 magically produces RS232 type signaling. A special type of device could be made but it would need to incorporate the chips necessary to convert USB to serial protocol and the necessary chip or circuitry to level shift the logic level signals from the USB<->serial chip to the +/- voltage swings expected on RS232 signals.

  • \$\begingroup\$ Thanks for the thorough reply. Any particular pin out diagrams or spec sheets you’d recommend to reference for attempting USB to RS232 conversion? I would potentially be interested in designing a PCB to be made for this \$\endgroup\$
    – SuperAdmin
    Commented Oct 18, 2022 at 19:34
  • \$\begingroup\$ @SuperAdmin - You should visit a site like ftdichip.com. They make all manner of USB to serial converter chips and related assemblies including PCBs. You should be able to find even schematics for some of their devices in the users manuals such as here; ftdichip.com/wp-content/uploads/2020/07/… \$\endgroup\$ Commented Oct 18, 2022 at 21:01

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