Krell KAS amplifier remote master slave conection

Hi

I own two mono blocks Krell KAS. On the rear panel there are two master / slave conectors. When the two mono blocks or other amplifiers are linked , one amplifier can control the turn on and off of the others. There is this possibility on the Krell KAS and the KSA S series.
My question is what kind of male connectors and cable is required to link the amplifiers ? This is difficult to identify looking at the Master/Slave female conectors on the rear panel and there is no information on the user manuals.
Thank you in advance