Leeb, we do not have a document on doing what you're attempting. When you remove the 9 (or any other set pilot digit), it can cause some overlap when dialing internal extensions since the first 3 digits of an area code would match the internal extension.
If you add a dial plan entry with $, that should allow you to complete any internal auto-attendant transfers or call coverage situations you might be attempting.
Leeb, you may want to look at two related document https://supportforums.adtran.com/docs/DOC-1828 and https://supportforums.adtran.com/docs/DOC-2931 . They are two separate documents but should help in your particular case.
Additionally, ADTRAN's next AOS release R10.8 for NetVanta 7000 series has a new feature, which allows you to easily change the steering digit using the installation wizard, and even set it to "none". This way, you dial an internal extension and an outside number the same way. Without any special "trunk Access" or "Steering" digit. The next release will be entering beta next week. If you are intrested, please contact your local ADTRAN sales representative and ask for their assistance for participating in the beta program.
You would need to still have a dial plan entry for 3 digit extensions for the Auto-Attendant and Call coverage but you would need to add an inter-digit timeout to this dial plan entry so analog device can make external calls. See the example below for making this change.
NV7100(config)#voice dial-plan 3 extensions MXX default
Now analog phones will still be able to dial 3 digit extensions but there will be an inter-digit timeout of 4 seconds before the call is sent or the user can dial a "#" to send the digits immediately.
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