Related Clues:

• It often precedes a three-digit number
• Part of a suite no
• Abbr. after a phone no
• Abbr. after a telephone no
• Office contact no
• No. after a phone no
• Call routing abbr
• Work phone no
• No. after a no
• Routing no. of a sort
• Second ph
• Directory abbr
• # after a #
• Phone no. adjunct
• Office no