Netopia 435 Reference Manual page 36

Dial...
Dial On Demand:
Initiate Data Service...
Callback:
Idle Timeout (seconds):
Select Initiate Data Service and choose the correct ISDN
bandwidth to use with this connection profile. In North America,
user's are not guaranteed of having a 64k connection to their
destination; only when 64k is not available from point A to point
B should 56k be selected. The Router auto falls back to 56k
when 64k service is not available. It is advised to select 56k
when you know that the 64k service will fail. You may also
select Speech if your line is provisioned for this feature and the
call is within you local ISDN region. This may allow users to
save money, but is not guaranteed to work outside of their
switch.
56K and 64K are data grade bearer capabilities. Speech is a
bearer capability that tells the telco network that the call will be
used for voice purposes. The telco network may apply echo
cancellation, compression, and other schemes that are not
appropriate for data. In addition, Netopia ISDN Router calls are
data-only; speech will not allow the Netopia to dial an analog
device.
Select Callback and toggle to Yes to drop incoming calls (calls
that the Netopia ISDN Router answers) and use this connection
profile to call the remote network back. (See
Configuring ISDN Connections
Telco Options
Dial In/Out
+-----------+
+-----------+
| 64 kb/sec |
| 56 kb/sec |
| Speech
+-----------+
300
2-21
|
"Answering calls"