Glad to hear you got things working. While serial might be obsolete for many things it was used for at one time, it's the lifeline for recovering any sort of embedded device. I did this exact same thing with my 7700s and restoring 3.3.4 never seemed to work. I had to restore 3.1.7 then upgrade from there. It was really weird, but the lack of username/password stems from a security change that Hikvision has implemented in the 3.3.x firmware versions. The concept is when you buy a product from them it has no default password. Ever. As such no one can just pick up a device and get inside and tinker. This comes to mind with every old school linksys (and some others too) router that you could connect to it and admin/password you were in no question. Anymore even just saying hi to someone is a security risk, every little thing has to be locked down anymore. While I think axing default passwords is a spectacular idea to improve device security, Hikvision did a horrible job of implementing such a security feature. I'm trying to think of something they have implemented in their products that was done in such a way that makes logical sense. I can't.
And for future reference, serial and TTL are similar, but not the same.
@djangel described this perfectly. If your NVR has a DB9 port on the back, it's RS-232 level and any old DB9 serial adapter will work. (I recommend ones with Proliphic chips in them, best support and compatibility IME). If it doesn't, almost certain it's TTL. I have yet to find an RS-232 enabled NVR that doesn't have the DB9 port on the back, so I'm assuming that to be the determinant.
New firmware is great. Finally took GUI design seriously. I never understood the old green leafy theme for the NVRs prior. I haven't used any of the super advanced features of the new one yet but I've read email alerts to be a touchy subject across the board. I don't have a need for those at the moment so doesn't affect me too much.
Sent from my iPhone using Tapatalk