This code system http://hl7.org/fhir/contact-point-system defines the following codes:

CodeDisplayDefinition
phonePhoneThe value is a telephone number used for voice calls. Use of full international numbers starting with + is recommended to enable automatic dialing support but not required.
faxFaxThe value is a fax machine. Use of full international numbers starting with + is recommended to enable automatic dialing support but not required.
emailEmailThe value is an email address.
pagerPagerThe value is a pager number. These may be local pager numbers that are only usable on a particular pager system.
urlURLA contact that is not a phone, fax, pager or email address and is expressed as a URL. This is intended for various personal contacts including blogs, Skype, Twitter, Facebook, etc. Do not use for email addresses.
smsSMSA contact that can be used for sending an sms message (e.g. mobide phones, some landlines)
otherOtherA contact that is not a phone, fax, page or email address and is not expressible as a URL. E.g. Internal mail address. This SHOULD NOT be used for contacts that are expressible as a URL (e.g. Skype, Twitter, Facebook, etc.) Extensions may be used to distinguish "other" contact types.