Codec Tieline Gateway User Manual page 187

5. Click the drop-down Line Type arrow and select your preferred option. Ask your Telco
whether your ISDN line is Point-to-Point or Point-to-Multipoint. By default select Point-to-
Multipoint, unless your switch type is an AT&T 5ESS custom point-to-point.
6. If you are in the US enter DN and SPID numbers as required, or in other regions enter DN or
MSN numbers as required.
7. Click Add an allow list entry to only accept calls from numbers in the Caller ID Allow
List Filter. All calls are accepted if there are no filter entries.
8. Click Save when configuration is complete.
Important Notes:
Directory Numbers and Multiple Subscriber Numbers
Directory Numbers (DN) in North America and Multiple Subscriber Numbers (MSN) in the
rest of the world are simply phone numbers associated with an ISDN B channel, like lines
listed in a typical phone directory. Your Telco will normally supply 2 DN/MSN numbers for
each pair of B channels. However, these numbers may or may not be associated with a
specific B channel.
Often broadcasters prefer to predict which B channel will answer an incoming call to
ensure audio routing is consistent. However, if a DN or MSN number is not entered in the
codec and multiple B channels are available, the codec may use any channel to answer
an incoming call. To ensure calls are routed consistently, enter a DN/MSN number
© Tieline Research Pty. Ltd. 2021
Gateway and Gateway 4 Manual v1.2
187