ENLARGE 
In addition to the inputs and formats included in the CP650D, the following digital audio formats are supported when the Cat. No. 790 is installed:
Format 80, Master Digital, automatically switches between varying bitstream types (two-channel PCM/Dolby Digital).
Format 81, Master Digital with Surround EX™, applies Surround EX decoding to Dolby Digital 5.1 bitstreams.
Format 88, Six-Channel PCM, inputs three AES-3 PCM channel pairs to comprise a 5.1 program.
Format 89, Six-Channel PCM with Surround EX, applies Surround EX decoding to AES channel pair number 3 (Ls/Rs).
Format 90, Seven-Channel PCM, inputs AES-3 channel pairs to comprise a 6.1-channel (Surround EX) program.
When a Cat. No. 790 card is installed, the digital bitstreams are input on the “Option I/O” D-connector.
The Cat. No. 790 adds Dolby Digital Surround EX decoding and four surround zone channels, each with 27-band equalization.
The CP650 automatically configures the four surround zones (Ls, Bsl, Bsr, Rs), depending upon the surround processing required. A single “mono” zone (Ls + Bsl + Bsr + Rs) is applied for Dolby Pro Logic® formats. Stereo surround zones (Ls + Bsl, Rs + Bsr) are configured for 5.1 formats, and three surround zones (Ls, Bsl + Bsr, Rs) are configured for Dolby Digital Surround EX formats.
When a Cat. No. 790 card is installed, the surround channels are output from the “Option I/O” D-connector.
The Cat. No. 790 also provides the expansion slot necessary to add the Dolby Cat. No. 791 Digital Crossover Card to your CP650.
The Cat. No. 790 is contained within the CP650 upgrade kit, “UEX/650,” and can be ordered from your Dolby distributor.