DIRECTV Set-Top Box Information for the Installer
DIRECTV, Inc.
March 5, 2008
Version 2.2
Page 38 of 42
DTV-MD-0058
8 Appendix: Low Speed Serial Port Specifications
8.1 Low-Speed Data Port Connector
The connector type on D10, H10 and HR21P is a standard DB-9F or RJ22 (4 way/4 position jack). The
pins for the DB-9F are as shown in Figure 8-1. The STB will use three (3) lines (L2-Rx, L3-Tx and
L5-Grnd) for bi-directional full-duplex communications.
Figure 8-1. Low-Speed Data Port Pin Assignment Diagram
Line positions, designated as “optional”, may be provided (but are not required to be provided) by the
STB as a convenience to source a “TRUE” state to those PC serial interface lines that may require a
“TRUE” state for data transfer. Figure 8-2 shows the orientation of the RJ22 (4 way/4 position jack).
Figure 8-2. Orientation of the RJ22 (4 way/4 position) Jack