Powerline adapter password/default key (Cisco HPAV-100)

I'm trying to upgrade my powerline network in my home. The provided AT&T adapter is only 200mbps. (Model: SerComm IP532CG).

I ran into trouble when setting up the new powerline adapters I bought. I did the reset process for all adapters but now one of the main adapters from AT&T can't be found on the network (the main one connected to the AT&T DLC-100 controller). Model: Cisco HPAV-100.

There is no password on the label on the back which there usually is (format xxxx-xxxx-xxxx-xxxx). There is no documentation for this device that I can find online.

I need to find the password for the Cisco HPAV-100 powerline device to add it to the network. Getting the user manual for the Cisco HPAV-100 would also be helpful.

Can anyone help?