The ID-4100 has an unusual scanning feature that can be assigned to a memory channel having to do with Skip.

Skip is a feature that makes the radio omit a channel during scanning. It is good to use for channels that have a great deal of traffic or noise to allow scanning to continue without interruption by a conversation you would rather not listen to currently. 

The options for Skip include
  • Off - The channel is included when scanning
  • Skip - The channel is omitted during memory scan
  • P-Skip - The channel is omitted during memory scan AND the frequency is omitted during VFO scanning.  
This option can be set independently for each memory channel.