Appendix A. Understanding Broadcast Mode and Direct Mode Connection
A.1 Broadcast Mode (the default mode)
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Broadcast Mode allows multiple master PC‟s running CommuniCenter and by default every master can
communicate to any substation. Broadcast Mode is named for its method of communication, UDP broadcasts. An
example single Local Area Network involving a switch and a DHCP server should not require any changes to the
default configuration of the IPW-1A adaptor. When the adaptor powers on it seeks an IP address and when it gets
one, it will begin broadcasting using UDP (default port 1724) to the entire broadcast domain.
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A broadcast domain is typically every device sharing a common hub or switch but nothing beyond a router or
gateway. If the network involves a Wide Area Network (more than 1 router) one option is to use a bridged Virtual
Private Network so that broadcasts are repeated between networks. IT professionals may be able to provide
additional methods.
A.2 Direct Mode
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Configuring the IPW-1A in Direct Mode allows the system to function when traversing multiple networks. Direct
Mode allows an intercom to communicate over a WAN or over networks not bridged without additional VPN
equipment. When working in Direct Mode, the intercom will only be able to work with a single designated PC. Over
a WAN, you must set each router to allow UDP traffic on (default) port 1724, and then forward traffic to the
appropriate destination PC running CommuniCenter.
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Other CommuniCenter PC‟s in the either LAN will not communicate with any intercoms set up in direct mode. If
multiple PC‟s are required to communicate with a intercom over a WAN, then you will need to set up a VPN or other
bridged connection between the networks and use the default Broadcast Mode.
A.3 What does the network administrator need to know?
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For Broadcast Mode: The adaptors and the computers running CommuniCenter must be in the same broadcast
domain.
Use this mode for full functionality,
including multiple master PC’s.
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For Direct Mode: The gateways and firewalls connecting the adaptor(s) and the computer running CommuniCenter
must have a port open (UDP 1724 by default) and if necessary, forwarding rules in place.
Use this mode if
extending the broadcast domain is not an option.
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Transport Bandwidth:
≈128Kbps per active session (normal mode)
≈64Kbps per active session (low bandwidth mode)
A.4 What functions are available in each mode?
Pg. 23
Feature
Description
Broadcast
Direct
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Multiple PC‟s
Multiple master PC‟s communicating to each substation Yes
No, single master only
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Call in
Call in from the substation or to the substation
Yes
Yes
o
Monitor
Listen to the substation
Yes
Yes
o
Talk
Speak (and listen) to the substation
Yes
Yes
o
Relay
Relay functions, door release or release on
calling, connecting or incoming audio
Yes
Yes
o
All Call
Speak one-way to all substations at the same time
Yes
No
o
Group Call
Speak one-way to selected substations
Yes
No
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Messages
Play .wav file to selected substations
Yes
One station at a time