Since ACF doesn’t natively support a phone field I created a field for it populated with a repeater with 3 numbers. These also feed a small director CPT.
The fields all function fine in any dynamic content situation I used them as the button text, as an example.
When I go to use them {{dc:looper:field key=“area_code”}}{{dc:looper:field key=“ph_prefix”}}{{dc:looper:field key=“ph_line”}} in the Phone link entry the Preview only shows the query and not the rendered numbers. This translates to a blank result for the tel: link when the site renders.
I tried a basic number field as well and it also remains blank so it seems a custom field cannot be used with the Tel: link currently.
You can perform a workaround by adding the Tel: prefix for the link manually i.e. tel:{{dc:looper:field key=“area_code”}}{{dc:looper:field key=“ph_prefix”}}{{dc:looper:field key=“ph_line”}}