Failing to make a hikvision DS-7300 DVR work with a Pelco ES31PC camera?

[gismail]

I have a set of hikvision DS-7300 DVRs. I'm trying to make them work with the pelco ES31PC cameras, in particular with the "Pelco-D PTZ" protocol via "two-wire RS-485" cabling, with which all my cameras have already been configured; but all my attempts had failed. Even though I managed to control other cameras by the same DVR.
I even managed to control the same Pelco cameras using another DVR.
So I'm asking for any advice that can help me resolve this issue.

 

[Phil]

It's not really our thing as we only work with IP cameras, but from memories of more than 15yrs ago:
The camera and the DVR probably allow you to set multiple protocol options e.g. Pelco P / Pelco D (I think there was a Phillips standard too)
Can you see the selections / options?
Are both devices set to use the same protocol?
I vaguely recall 'Preset 91' on Pelco PTZs to access some settings?