This shows a listing from the 1920 Chronicle for China, which is mainly Shanghai and Treaty ports but also has some Hong Kong listings. I can see the notation about the telephone numbers being posted via newspaper ads.
Date picture taken
1920s
Gallery
Comments
Hong Kong Telephone Directory 1946
Seems HKU Library didn't keep pre-war directories
JOURNAL:Hong Kong telephone directory.
Check holdings at Special Collections Special Collections Hong Kong Serials (HKS 384.6025 H7 T2)
https://julac-hku.primo.exlibrisgroup.com/discovery/fulldisplay?docid=a…
Special Collections
May be available , Special Collections Hong Kong Serials, HKU ; HKS 384.6025 H7 T2
Summary holdings:
1946-1947,1949,1956,1965,1970-1976,1976/1977-1978/1979,1979-1993,1994/1995-2004,2006-2007,2015-2018...
HKU Library also keeps other directories
https://lib.hku.hk/files/hkspc/pathfinders/HK%20Directories.pdf
10
香港商務人名錄 : 庚午年 = Commercial directory 1930, Hong Kong.
香港 : 香港商務人名錄公司 [1930]