As per TPlink website, the router is compatible with the Dlink dongle DWM156(see compatibility list for Singapore) or [...]. They also suggested to download and apply the corresponding file from the bin [...] in case it does not work even with the latest firmware.
I tried all these combinations but nothing worked. The router could detect the dongle properly but while trying to 'connect' to internet, it is failing. In log it is saying that 'Access Number' and 'APN' are wrong. But I checked these values for my ISP (Vodaphone) and found to be okay. By the way, the dongle is working fine while being used directly with my laptop or PC.
I contacted TPLink support (firstname.lastname@example.org) but they replied that card is unlocked data card and all unlocked data cards are not compatible with all their routers. Their router can support only locked data cards which are provided directly with ISP like, Tata Photons, Docomo, Airtel, Aircel, Idea Net Setter, Vodafone etc.
Fact is, DLink DWM156 always has to use independent SIM (as it does not has built in SIM) and if it is declared to be compatble in Singapore, why it is not working here.
I further enquired this with TPLink service team but they never came back with any answer.