PDR-885 Protocol for XDS V-Chip Support

This document outlines the method for loading data into the PDR-885 for Extended Data Services (XDS) encoding in general and Program Rating (V-Chip) data encoding in particular. For complete XDS packet information, consult Electronic Industries Association documents EIA-608 "Recommended Practice for Line 21 Data Service" and EIA-744 "Transport of Content Advisory Information Using Extended Data Service (XDS)".

Loading XDS Packets

XDS data loading is initiated by transmitting the ASCII string: CTRL-A V 1

(The Hexidecimal equivalent is: 01h 56h 31h.)

This is immediately followed by an XDS packet. The packet should begin with the appropriate XDS class code (one byte) followed by the appropriate type code (one byte). The actual data is loaded next, and my be up to 32 characters depending upon the particular packet. Individual data packets are terminated by the XDS "end" control code, 0Fh. The encoder will frame the packet by adding a null byte (if necessary) and generate the required checksum. Subsequent packets are handled in the same manner, each beginning with the class/type code pair and terminating with the "end" code. The last "end" code should be followed by an ASCII carriage return (0Dh) which will terminate data loading. Any or all of the following XDS data packets my be stored in the PDR-885:

• Start time/Program ID [01h 01h]

• Length/Time in show [01h 02h]

• Program Name [01h 03h]

• Program Type [01h 04h]

• Program Rating [01h 05h]

• Network Name [05h 01h]

• Station ID [05h 02h]

• Time of Day [07h 01h]

Up to eight packets may be loaded. The encoder will allocate sufficient memory for each packet and will keep track of the number and type of packets loaded. Repetition rates will depend upon the packet and will follow EIA-608 guidelines. Data updates (including time of day) will be totally dependent upon the host PC. Otherwise, stored data will be encoded indefinitely. To update a packet, simply reload it using the protocol outlined above.

Removing Loaded Packets

To remove or delete a packet, transmit the following ASCII string:
CTRL-A V 0 xx yy (CR)

(The Hexidecimal equivalent is: 01h 56h 30h xxh yyh 0Dh.)

Data qualifiers xx and yy represent the appropriate class/type code pair and (CR) represents an ASCII carriage return. To completely clear the XDS buffer, omit the class/type characters and simply transmit ^AV0 followed by a carriage return.