5.8.9.6. Suffix Dialing To Remote System 
Because lines with loop start signaling do not have any criteria for
end-of-dial (evaluated or not evaluated), the OpenScape 4000 can be in
the 'talking state' although the remote system is in the busy
or ringing state. Now you can use remote system features with suffix
dialing.
IMPORTANT:
Send the (suffix) dialing to the remote system
with the signaling method (-outgoing: DIP or DTMF) that is assigned to
the line. This is not a cross-network feature. If you have configured
a line for suffix dialing (COT: OVRA & USD set), then every dialing
is sent to the remote system as suffix dialing. This means that features
that are controlled by suffix dialing are not possible in the OpenScape
4000. This affects redial, tracing, and DTMF transmission.