Hi @Kat79 

Thank you for your question. 

You can bring your own modem as long as it follows te following

• Compatible with the NBN network and your NBN connection type
• Not locked to another internet provider
• Can support the connection speeds on your plan (otherwise you may experience slower speeds)

It is important to know that we can't remotely connect to a modem that you bring which will mean

• We won't be able to do our regular tests and checks
• We can only provide general troubleshooting advise
• You need to let us know if your NBN service is experiencing issues

I hope this assists in your question. 
Thanks, Chris