# What are Networks?
The main network you can access through the signer is the Aleph Zero blockchain. This is the default network, but you can change the network to the others that are supported. You can interact with the Aleph Zero Testnet and connected networks that use the Substrate framework or are a part of the Polkadot ecosystem.
For example, accessing the Aleph Zero Testnet will permit you to interact with apps that have been released there and are currently in the testing phase. To learn how to get access to the Testnet, head over to our testnet website:
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