Each line in a vCard is a separate component of the vCard. A component line consists of three things:
the component type-defnition (N, ADR, TEL, etc);
optionally, parameters for the component, such as whether or not the data is binary-encoded, or the type of data (home/work/preferred/etc), and so on; and
the component value (which may be a single text value, repeated text values, or a structured text value).
For example, consider the following component lines:
ADR;TYPE=WORK,PREF:;;123 Main;Beverly Hills;CA;90210;US EMAIL;TYPE=HOME;TYPE=INTERNET:email@example.com CATEGORIES:Personal,Business,Family PHOTO;TYPE=JPEG;VALUE=URI:http://example.com/photo.jpg
Component line 1 has an ADR type-definition (meaning a delivery address). It has a TYPE parameter of WORK and PREF, indicating that this a work address and is the preferred address for deliveries. Finally, the value of the component is a structured text value. Structured text value parts are delimited by semicolons; in the case of ADR components, the structured value parts are p.o. box, extended address, street address, city/locality, state/region, zip/postal code, and country.
Component line 2 has an EMAIL type-definition (meaning an email address). It has a TYPE parameter of HOME and INTERNET (meaning an internet email address for home). The component value is a single text value indicating the email address.
Component line 3 has a CATEGORIES type-definition (meaning the general categories of of this vCard). There are no parameters for this component. The component value is a repeating-text value. Repeated text values a delimited by commas.
Component line 4 has a PHOTO type-definition (meaning a personal photograph). The parameters indicate that the photo TYPE is JPEG (giving a hint to vCard decoders how to handle the PHOTO value) and that the component VALUE will be a URI (that is, a link to an external photo file). Finally, the component value is a single text value, revealing in this case the URI of the photo.