There are two Silver remotes. THe one with the white/silver menu button requires four digit codes, the one with the red menu button requires 5 digit codes. It took several hours for me to figure why my red button would not "blink twice" with 4 digit codes. See links below. Hope this helps everyone not wast their time:

White/silver menu button:
[Link: comcast.com]


Red Menu button:
[Link: cdn.comcast.com]