Are these on every pole of just one or two every few km?
What are the nearby buildings? Commercial shophouses/factory lots, business centres or just homes directly in front of them?
They seem like termination points for wiring up mobile base stations or providing end to end leased lines for commercial sites such as banks etc.
Celcom Timur is a joint venture between Sabah government and Celcom in East Malaysia which deals with laying dark fibre for leasing. They're not into providing internet and ISP business but leased their dark fibres to other ISPs/telcos who needs them for backhaul.
If you're interested to know more why not contact them by phone directly or give them a visit?
Celcom Timur SabahAddress:
Lot 100, Block K, Alamesra, Lor Plaza Permai 3 & Sulaman-Coastal Highway, Alamesra, 88400 Kota Kinabalu, Sabah, Malaysia
Contact: +60 88-484 999
In Sarawak, they've a sister company called Sacofa instead.
https://www.sacofa.com.my/web/Nothing on their site saying that they're providing internet services except fibre leasing and backhaul links for mobile base stations.
These pictures are from a housing estate. Notice that there is a Celcom Timur D.P. box every five houses or so along this
particular street which fronts roughly 40 houses. There are 4 other shorter streets with roughly 10 houses each.