User's Manual
RealPresence Collaboration Server (RMX) 1500/2000/4000 Administrator’s Guide
19-26 Polycom, Inc.
In addition, PSTN participants can dial the Gateway IVR and can use the MCU or DMA 
prefix in the gatekeeper together with the conference ID/endpoint alias as the destination 
string to simplify the input. This is one of the methods for PSTN participants to connect to a 
virtual Meeting Room on the DMA. For more details, see "PSTN Dial-in Using GK Prefix” on 
page 19-9.
Calling a DMA Direct with Automatically Generated Destination Dial Strings 
In this configuration, the gateway session initiator enters one of the dial-in numbers 
assigned to the gateway profile. This number is truncated by the Collaboration Server 
gateway and the truncated digits are replaced by a prefix that corresponds either to the 
DMA prefix in the Gatekeeper. 
Figure 21 Call Flow from ISDN Endpoint to Polycom DMA with Automatically
Generated Forwarded Dial String
Example:
Figure 1 shows the call flow assuming the following parameters:
First Dial-in Number  5705550
Last Dial-in Number   5705560
Use Dial-in Numbers as Destination ID   Selected
DMA Meeting Room ID   5555
Destination Prefix (DMA prefix in Gatekeeper) 26
Number of Rightmost Digits to Append  4
PSTN participant dials   (212)5705555
Number that will be used by Collaboration Server to forward 
the call to the DMA     265555
Calling the DMA via Gateway IVR
Audio PSTN/ISDN calls can be routed to Polycom DMA 7000 via the Collaboration Server. 
ISDN Video endpoints connect using their audio channels (but consume video resources). 
The DMA 7000 enables load balancing and the distribution of multipoint calls on up to 10 
Polycom Collaboration Server media servers.










