Control Hub normalizes Webex Calling and Webex Contact Center numbers into E.164 format, and Cisco's voice channel setup guidance explains that numbers routed from Cloud Connected PSTN or Local Gateway are provisioned in +E.164 format for Control Hub. The fully qualified +1-450-783-2223 format is therefore valid. Cisco interfaces also accept common national display formatting for number entry in many workflows, such as parentheses around the area code, which corresponds to (450) 783-2223 in the option set. The bracketed version, hash-prefixed value, and dotted format are not acceptable telephony number formats for configuring a Webex Contact Center entry point number. The key is that the number must represent a valid PSTN telephone number that Control Hub can store and map to the entry point. The +E.164 version is the canonical final representation; the national style is an accepted entry/display form. Reference: Cisco Help, Set up voice channels for Webex Contact Center; Set up voice settings for Webex Contact Center.