text: Constant suffixes used in Sino-Korean ordinal numerals
  Beon (), ho (), cha (), and hoe () are always used with Sino-Korean or Arabic ordinal numerals. For example, Yihoseon () is Line Number Two in a metropolitan subway system. Samsipchilbeongukdo () is highway number 37. They cannot be used interchangeably.
  is 'Apt #906' in a mailing address. 906 without ho () is not used in spoken Korean to imply apartment number or office suite number. The special prefix je () is usually used in combination with suffixes to designate a specific event in sequential things such as the Olympics.
  Substitution for disambiguation
  In commerce or the financial sector, some hanja for each Sino-Korean numbers are replaced by alternative ones to prevent ambiguity or retouching.
  For verbally communicating number sequences such as phone numbers, ID numbers, etc., especially over the phone, native Korean numbers for 1 and 2 are sometimes substituted for the Sino-Korean numbers. For example, o-o-o hana-dul-hana-dul () instead of o-o-o il-i-il-i () for '555-1212', or sa-o-i-hana () instead of sa-o-i-il () for '4521', because of the potential confusion between the two similar-sounding Sino-Korean numbers.
  For the same reason, military transmissions are known to use mixed native Korean and Sino-Korean numerals: