My question concerns markup that surrounds some of the default phone number labels in the Person entries of the Contact list on the iPhone.

I have created an iPhone contact list address book entry for a person, "John Smith" with the following phone number entries:

• Mobile (604) 123-4567
• iPhone (778) 123-4567
• Home (604) 789-4561
• Work (604) 456-7891
• Main (604) 789-1234
• megaphone (234) 567-8990

Note that the first five labels are default labels provided by the Contacts application and the last label, "megaphone", is a custom label.

I wrote the following method to retrieve and display the labels and phone numbers for each person in the address book:

-(void)displayPhoneNumbersForAddressBook {
    ABAddressBookRef book = ABAddressBookCreate();
    CFArrayRef people = ABAddressBookCopyArrayOfAllPeople(book);
    ABRecordRef record = CFArrayGetValueAtIndex(people, 0);
    ABMultiValueRef multi = ABRecordCopyValue(record, kABPersonPhoneProperty); 
    NSLog(@"---------" );
    NSLog(@"displayPhoneNumbersForAddressBook" );

    CFStringRef label, phone;
    for (CFIndex i = 0; i < ABMultiValueGetCount(multi); ++i) {
            label = ABMultiValueCopyLabelAtIndex(multi, i);
            phone = ABMultiValueCopyValueAtIndex(multi, i);
            NSLog(@"label: \"%@\"     number: \"%@\"", (NSString*)label, (NSString*)phone);
            CFRelease(label);
            CFRelease(phone);
    }
    NSLog(@"---------" ); 
    CFRelease(multi);
    CFRelease(people);
    CFRelease(book);
}

and here is the output for the address book entry that I entered:

2010-03-08 13:24:28.789 test2m[2479:207] ---------
2010-03-08 13:24:28.789 test2m[2479:207] displayPhoneNumbersForAddressBook
2010-03-08 13:24:28.790 test2m[2479:207] label: "_$!<Mobile>!$_"     number: "(604) 123-4567"
2010-03-08 13:24:28.790 test2m[2479:207] label: "iPhone"     number: "(778) 123-4567"
2010-03-08 13:24:28.791 test2m[2479:207] label: "_$!<Home>!$_"     number: "(604) 789-4561"
2010-03-08 13:24:28.791 test2m[2479:207] label: "_$!<Work>!$_"     number: "(604) 456-7891"
2010-03-08 13:24:28.792 test2m[2479:207] label: "_$!<Main>!$_"     number: "(604) 789-1234"
2010-03-08 13:24:28.792 test2m[2479:207] label: "megaphone"     number: "(234) 567-8990"
2010-03-08 13:24:28.793 test2m[2479:207] ---------

What are the markup characters

_$!< and >!$_

surrounding most, save for iPhone, of the default labels for?

Can you point me to where in the "Address Book Programming Guide for iPhone OS" I can find the information?

Thank you for your help.