using extensions in phone number fields - e.164 format

[shembop]

I have our phone number fields in the e.164 format, and now someone needs to add an extension (phone# - ext)

How can I do this without adding a field? Multiple down sides of just adding a field.

[Brad Tilton]

I don't think that field type supports extensions, so you're probably stuck with an additional field for the extension.

[kevan_smith]

This is an old thread, but I'm prepping for Notify/Twilio and had the same question.  In the end I came to the same conclusion as Brad but adding the "why" here.  Hopefully it saves someone a bit of time.

The e.164 field is technically a string field and you can make it as long as you want.  However, when you edit the field, country codes, long distance codes, and non-numerics all get stripped, and the result gets passed through the Telephone Display Rules.  So... for each of your Phone Territories you can add a Phone Format that allows for the extension.  For example:

<format>($1) $2-$3 x.$4</format>
<name>US availableFormats</name>
<order>120</order>
<pattern>(\d{3})(\d{3})(\d{4})(\d+)</pattern>

What that does is take any number after the 10th digit and assumes it's part of an extension, right or wrong. 

Here's the rub...

1. Since all non-numerics (such as ",") get stripped, you can't introduce wait periods (which is a limiting factor for some extensions)
2. According to the official ITU E.164 recommendation, the phone number must be number up to fifteen digits in length starting with a ‘+’.  That's not enough space for extensions, and assuming this is for Notify (e.g. Twilio), that's a real problem.  Twilio strictly follows the e.164 standard.

What you can do is send Twilio the regular e.164 compliant phone number, and then pass it the extension/waits/etc after the receiver picks up.  You can probably parse your modified e.164 phone number before handing off to Twilio, but that's getting a bit too deep in the weeds for me.  Easier and more reliable to just use an additional field for the extension, as Brad so succinctly suggested. 

[VaranAwesomenow]

Thanks Kevan for this answer !