Proposal to replace documented syntax for telephone extensions

[Jofban]

@Minh_Nguyen

• Allow an actual tel: URI for any phone number that can’t be represented by E.123 notation, such as phone=tel:+1-888-828-4798,2334.

Perhaps a subkey like phone:tel=+1-888-828-4798,2334 for machine-readable numbers in the tel: URI format? Doesn’t solve the issue of old parsers, but buys us flexibility to leave the main phone key human-readable.

@Minh_Nguyen

• Choose some other delimiter that doesn’t already have a special meaning, such as a comma (which would be consistent with tel: URIs) or x (a very common North American notation).

The character | is used as delimiter for lanes or rather their properties. I think that usage parallels its use here, and fits better than ;. (W.r.t to how to separate the different phone numbers; this could allow ; again)

@Minh_Nguyen

• Refer mappers to the E.123 notation, ext. or the local translation, expecting data consumers to equate any xzy. with ext. and extract the extension number.

I’d expect data consumers to do that mostly anyhow, so having this for phone is probably fine.