What is a "pseudo" channel

When I execute the “zap show channels” command from the CLI I see something like.

iti-ibex01*CLI> zap show channels
Chan Extension Context Language MusicOnHold
pseudo att_sip

I am wondering what the “pseudo” is referencing. The “att_sip” is a context in extensions.conf.

I have 191 zap channels configured on this system and they all look correct but this “pseudo” is a question.

pseudo channels are a channel that lets * obtain timing from a Zaptel device or ztdummy. It’s not a call. You will see a dummy channel when there are active MOH or MeetMe.