Currently, the Xero connector does not pull over phone numbers for contacts. There is a "Phones" field available from the Contacts endpoint, see below:

https://developer.xero.com/documentation/api/accounting/contacts#overview
https://developer.xero.com/documentation/api/accounting/types#phones

In the example response for GET Contacts, it shows Phones information in there and looks very similar to Addresses. Given that info from the Contacts endpoint is already being pulled in, and Addresses is currently being handled through another table (contact_address), I assume it would be pretty easy to create another table for Phones (eg contact_phones) pretty easily.

Phone numbers are useful for sales outreach.