Supplier's Contact Query of R12's TCA Architecture:

select hzr.object_id        party_id_for_vendor,
       hp.party_id          party_id_for_person,
       hp.person_first_name,
       hp.person_last_name,
       hcpp.phone_number    primary_phone_number,
       hcpe.email_address,
       hcpp.PHONE_AREA_CODE,
       hcpp.PHONE_NUMBER,
       hcpp.PHONE_EXTENSION,
       hp.party_name,
       fu.user_name
  from hz_parties               hp,
       fnd_user                 fu,
       hz_relationships         hzr,
       hz_parties               hzr_hp,
       hz_party_usg_assignments hpua,
       HZ_CONTACT_POINTS        hcpp,
       HZ_CONTACT_POINTS        hcpe
 where hp.party_id = hzr.subject_id
   and hzr.object_id = 431710 -- Supplier's party_id
   and hzr.relationship_type = 'CONTACT'
   and hzr.relationship_code = 'CONTACT_OF'
   and hzr.subject_type = 'PERSON'
   and hzr.object_type = 'ORGANIZATION'
   and hzr_hp.party_id = hzr.party_id
   and fu.person_party_id(+) = hp.party_id
   and hpua.party_id = hp.party_id
   and hpua.status_flag = 'A'
   and hpua.party_usage_code = 'SUPPLIER_CONTACT'
   And hcpp.OWNER_TABLE_NAME(+) = 'HZ_PARTIES'
   And hcpp.OWNER_TABLE_ID(+) = hzr.PARTY_ID
   And hcpp.PHONE_LINE_TYPE(+) = 'GEN'
   And hcpp.CONTACT_POINT_TYPE(+) = 'PHONE'
   And hcpe.OWNER_TABLE_NAME(+) = 'HZ_PARTIES'
   and hcpe.OWNER_TABLE_ID(+) = hzr.PARTY_ID
   And hcpe.CONTACT_POINT_TYPE(+) = 'EMAIL'
   And hcpe.status(+) = 'A'
   And hcpp.status(+) = 'A'