From inside (document excerpt):
Comcast Custom DVR 3-Device Universal Remote Control. Users Manual.
Overview
The Comcast Custom DVR 3-Device universal remote will control up to three home entertainment devices, including a Digital Video Recorder enabled Cable Box (used by Comcast Systems).
The remote control requires installing two (2) new AA batteries (included) and some easy programming to control
your devices. For best results, please read and perform all instructions listed here. Also, keep this guide for future reference.
Table of Contents
Installing Batteries
Features and functions
Programming device control
Searching for your code
Checking the codes
Changing volume lock
Reassigning device keys
Programming channel control lock
Troubleshooting
Manufacturer’s codes
Setup Codes for Audio Receivers
Setup Codes for Cable Boxes
Setup Codes for DVD Players
Setup Codes for Home-Theater-In-A-Box Devices
Setup Codes for PVRs (or DVRs)
Setup Codes for TVs
Setup Codes for VCRs And TV/VCR Combos
Source: comcast.com