Does A68 require a CP100 so downvison sonar will work?

I just had a Raymarine A68 installed. I was under the distinct understanding that Chirp Downvision sonar was built into the A68 and with the right transducer would display sonar on the screen.

My dealer installed a CP100 in addition to the A68, and the sonar seems to be working, but was the CP100 necessary? I thought the A68 made eliminated the need for the CP100 sonar module.

Please advise asap as I need to discuss this with my dealer right away.

Thanks in advance for your help!