Having set the correct CTCSS side tone try sending it DTMF tones. If the gateway is idle then sending it a * will prompt it to identify itself, this is a good test for access. If its connected to another echolink node then sending * will have no effect, in that case you can always hangup the link with #. Sending a node number as DTMF tones will connect you that gateway, see this link for a list of currently active nodes. Send 001 to connect to one of my favourites at random.
This page details the DTMF functions in full.
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