DIRECTV R15 Installation Guide - Page 13

DIRECTV Set-Top Box Information for the Installer 4.4 Multi-Tuner Data Port Commands A new set of commands are introduced for multi-tuner STBs, such as R15 and HR20. For multi-tuner STBs, the tuner needs to be identified for many of the commands as an input parameter. To maintain backward compatibility, new commands with the suffix "MT", have been created that have a TunerID parameter added. In the case where an original non TunerID command is issued to a multi-tuner STB, it will be executed as the equivalent "MT" command with TunerID set to 0x01. The [TunerID] shall start at 0x01 and increase in value by one for each additional tuner (i.e. 0x01, 0x02, 0x03...). The [TunerID] can be obtained by issuing the command GetTuner. See Table 4-1 for the list of STBs that support the multi-tuner commands. Table 4-4: Multi-Tuner Commands Summary Comman d Code Command Label Description 0x9A GetTuner Get the number of tuners and their designations. 0x8A GetPrimaryStatusMT Get the status information of current channel. 0x8B GetCurrentChannelMT Get the major and minor numbers of the tuned channel. 0x9D GetSignalQualityMT Get the signal level for the tuned channel. 0x9F OpenUserChannelMT Tune to a channel by inputting a channel number. 4.5 Default Data Rate and Format All STBs have a default data rate of 9600. The data format is 1 start bit, 8 data bits, no parity, 1 stop bit, and no handshaking. 4.6 Command Protocol The STB will use the command and data acknowledgment protocol for flow control as specified in Figure 4-1. Any controller that is implemented to control DIRECTV STB, should follow the protocol depicted in Figure 4-1. DIRECTV, Inc. Version 2.2 Page 13 of 42 March 5, 2008 DTV-MD-0058