Dad bought a security system online last month.
He forgot the seller and the box doesn’t list anything so I can’t contact the seller for help.

Finally, I got the time to install the system. It’s basically an H.264 recorder with five security cameras. I installed the cameras with the cables they provided and I do n’t have a distance problem.

However, when I booted up I got no signal message on the recorder for all the cameras.
Then I’ve gone through the user guide several times as well as the settings.
But still, no video!

Then I contacted a nearby alarm security systems company for help.  But they are saying it's better to change recorder.
what do you think?
Any suggestions are appreciated.