Locked?

[mikejstam]

I have a dual SIM card phone. Since activating a Boost SIM card I am unable to use any other sims. Is th3 phoned locked whilst the Boost SIM card is in the phone?

[DrQ]

All three network owners in Australia have discontinued 2G and many dual SIM phones only run on 2G on the second SIM card. If your phone is one of these it would mean none of the carriers would work in the second SIM card slot now they have no 2G.

[mikejstam]

Many thanks for your reply. I’m English and visit Oz every year. I keep my UK SIM card in the phone and then purchase an Oz card (normally Amaysim) for calls etc whilst I’m here. I’ve never had this problem before when mixing sims.

[DrQ]

Amaysim run on the Optus network who discontinued their 2G network as of about this time last year. Vodafone were the last and they have since discontinued theirs as well.

It could also be caused by limitations on the bands used, if the phone does support 3G on both sims it could also be that the phone supports 900Mhz but not 850Mhz as Optus uses 900Mhz as its standard and Telstra (the network boost is on) uses 850Mhz.

If you are unsure if you post the model number of the device happy to have a look for you.

[mikejstam]

Many thanks for your help. The phone I have supports 4g and the SIM cards indicate this. I’m not sure you will recognise the phone though - it is a Fusion5.  Again, thanks.

[DrQ]

I have heard of Fusion5, however, they aren't very upfront with their phone specs. It says it is 4G compatible but doesn't specify if both SIMs are 4G or what frequencies it is able to work on... looks like they don't have it listed anywhere. Only suggestion I could make would be to try a $2 SIM from an optus dealer or vodafone, if that works it means that the 3G is on 900Mhz only and not on 850Mhz, if it doesn't work either, it means that the second SIM is 2G only.  Alternatively you could swap the SIMs so the Boost is first and your UK one is second, that would give the same information if the Boost one works but the UK one doesn't it means it is 2G only in the second.