VTO2000A + VTH1560BW - video issues when calling VTO->VTH, opposite direction is ok


Jul 8, 2019
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Hi all,
I have following setup:
Outside: VTO2000A - firmware V4.300 (new one with SIP)
Inside: VTH1560BW - firmware V4.300 (new one with SIP)

Wired with CAT6 and CAT5 cable.
After firmware upgrade I performed factory reset on both.
Both see each other in terms of configuration, no apparent issues reported on VTH, they see each other in the network.
gDMSS/imou configured on one phone, works fine with VTO.

  • VTH (inside) -> VTO (outside) call (using monitor button in VTH) works fine:
    • video: framerate seems to be fine
    • sound is ok in both sides of connection
    • remote opening of the door lock is ok
  • VTO (outside) -> VTH (inside) call is unusable, issues found:
    • video: it show VERY low framerate, usually only first frame is presented on VTH till the end of the call
    • sound: very low quality, sometimes broken, generally unusable for both sides of connection
    • remote opening of the door lock sometimes works, sometimes VTH is reporting error with opening the lock
What I tried:
  • rewired all the connections, no issues,
  • tested if wiring is ok via automated tool for RJ45 checks (it's testing every wire one-by-one) & connection speed via notebook - no issues found
  • did factory reset both VTO & VTH
  • changing VTO's video codec, resolution, framerate - no improvement
  • double checked 12V power, no issues found
  • had similar issues on old 3.X firmware, it was even worse - VTO->VTH connection was not working at all, firmware upgrade helped a bit

At first look it was similar to issues related with connection stability / wiring, but it should be happening in both directions, hence I rewired everything, but no luck.

Any ideas what could be messed up?
It's super weird that in one way works fine.

Please advise, I ran out of ideas ...


Pulling my weight
Oct 19, 2017
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You did alrady everything obvious to eliminate the problem - now you have to dig deeper.
Assuming you are using the VTO's internal SIP server I would get wireshark / tcpdump traces from good and bad case and compare them.
This would get you one step ahead.
Off course you could also use the dahua json debug console , there are some cool debugging functions in it that can help you (e.g. setDebug->bitrate).
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