A number of DBS, POSB and M1 customers also experienced service outages on Wednesday, but these were understood to be unrelated to the fire at SingTel's Bukit Panjang Internet exchange last Wednesday.
Banking users had difficulties using DBS services at ATMs in areas such as Choa Chu Kang and Eunos around noon on Wednesday.
In a Facebook post at 3.30pm, DBS acknowledged the problem, attributing it to "a system connectivity issue" and that services were "intermittently disrupted for about 30 minutes". The bank did not elaborate on the extent of the problem.
M1 said its 3G mobile services were disrupted for about three hours on Wednesday morning in Ang Mo Kio, Yishun and Woodlands. The mobile services were restored as of 9.15am.
The telco said the disruption happened after a scheduled network upgrade of its radio network controller led to "intermittent connectivity issues".
Many frustrated M1 customers posted on its Facebook page to complain that they could not make calls or use messaging services such as WhatsApp.
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