Setting phone to default to No Account by default when Off Hook

[InterLynx]

I have a customer who is using T21 phones (although I assume this question could apply to any device) and has 2 accounts configured on the device. By default, when he picks up the handset to make an outbound call, the phone gives him a dial tone for line 1. We know how to change this to default to line 2 by using the right and left arrow keys. However, he'd like to be able to set the default to neither account or line. When he picks up the handset, he'd like to have no dial tone until he selects one of the two line buttons.

I've gone through the forums and can't find anything. I've also scoured the web interface and have found nothing. But it might just be labeled something that I'm not recognizing.

Has anyone ever tried to accomplish this? And if so, how?

Thanks for your response and feedback.