I installed Windows XP SP3 in a VM, and was able to connect with IE6.  Updated to the latest firmware (01.16.0001), but was still unable to connect from any modern browser via HTTPS.   However, using IE6 on XP, I was able to set the "Securty Mode" to "Full authentication" instead of "SSL and full authentication" (Under "Access Control" menu), and now I'm able to connect via any browser using HTTP.  Kinda junky that this is how I have to use this card now, just to maintain access, but it works.  
I've had a 1920W Tower UPS for some time now, and recently added a NMC (Network Management Card) to it.  I am able to get a console connection to the NMC, where I "Return to Default Configuration", set new network configuration, and restarted the card.  From there, I am able to hit the webUI of the card, but Chrome (and Safari and Firefox) all stop the page from loading.  Chrome, specifically, gives me this error: ERR_SSL_PROTOCOL_ERROR My best guess is that the card, running firmware 01.04.0007, is trying to use SSL v3 which is disabled in any modern browser, and possibly has an expired self-signed cert.  I have no way to get into the card. From countless Google searches, I've now installed the Dell Multi-UPS Management Console (MUMC) on a Windows 10 VM (I have no physical Windows assets available to me at this time), and am able to see the UPS within the Node List.  I've updated the access info (to admin/admin, as I've reset all settings to default with the NMC) and when I hover over the little key icon, it says "Access OK".  I've downloaded the most accurate NMC firmware I could find for this specific UPS, available from here (ftp.dell.com/.../).  So I upload this firmware to MUMUC, but when I select the firmware to install it to my UPS, I get a red exclamation point under "Upgrade status" and it won't let me install it.  Hover over it and it says "The selected firmware is not compatible with this device".    What are my options here?  How can I get into the NMC webUI so I can configure, use, and snmp poll this card for info?  I've spent 2 hours trying various things with this today, and I'm beyond frustrated.  It should not be this difficult...
How to update firmware on Dell 1920W Tower UPS Network Management Card 
(NMC)?????