With the dawn of the wireless technology, everyone can own mobile phones. Wired phones now are only used for offices and homes.
While caching around Singapore there are only few spots where a full structure of phone booth are still erected.
The first, I found was around Jalan Kayu near GC3NDCD - "So 'kayu'" cache. Initially I planned to installed a geocache here however it was so near to other cache.
The other one is when I'm trying GCTAPG - "Flying Saucer" cache. Be stealthy when retrieving the cache as the surroundings might be muggly.
You can add notes when you found another phone booth (with or without photo) and just reference the nearest cache.