Clear-Com BS850 (Last time buy) - Manual (Page 34)

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Cascading Multiple Base Stations
Two or three base stations may be cascaded to effectively increase the number of available receivers without
increasing the number of base transmitters. Cascaded bases behave like a single base with up to twelve receivers.
In a cascaded system, one base is configured as the Master and the additional bases as Slaves. Only the
transmitters in the Master are used. Any transmitters present in the Slaves need to be disabled to prevent
interference with this or other systems. Because only the Master transmitters are used, receiver audio from the
Slaves must be distributed to the Master for retransmission to other Beltpacs. A data cable connected between
the Master and Slaves allows audio routing requests and status to be communicated.
The PRO850 supports two methods of distributing audio from the Slaves to the Master. These are called “Aux
Distributed” and “2-Wire Distributed”. Each approach has its own advantages and disadvantages. For a quick
temporary setup where not all features are required, “Aux Distributed” is the simplest choice. In a permanent
installation where most features are needed, “2-Wire Distributed” is the preferred method.
Aux Distributed Set Up
The Aux Distributed configuration is simpler than 2-Wire Distributed, but has more feature limitations.
ISO+ is not supported in an Aux Distributed configuration. Also, there are restrictions on simultaneous
conversations from multiple Beltpacs. For instance, if one Beltpac user on a Slave base is currently talking
on intercom channel 1, other users on Slave bases will be unable to talk on channel 2. They will be
restricted by the system until the first user finishes. However, they may join in on the conversation on
channel 1 or listen to channel 2 without restriction. These restrictions are because only a single audio path
exists between the Slaves and the Master. Restrictions are enforced automatically by the system. A user
attempting to talk on a restricted channel will hear a busy tone upon pressing the Beltpac button.
To set up the system for Aux Distributed operation, configure one base as Mstr: Aux Dist n Slave(s) (see
page 15) and select correct number of Slaves (one or two). Then configure one Slave base as Slave1: AUX
Dist. If there is a second base, configure it as Slave2: AUX Dist. Note that there can only be one Slave1
and one Slave2. Connect an audio cable from the auxiliary input of the Master base to the auxiliary output
of Slave1. If Slave2 is present, connect an audio cable from the auxiliary input of Slave1 to the auxiliary
output of Slave2.
2-Wire Distributed Set Up
When a system is configured for 2-Wire Distributed operation, it has most of the features of a stand-alone
base. However, the wiring is somewhat more complex and there are still some feature limitations. In this
mode, receiver audio from the Slave bases is distributed by way of the auxiliary inputs and outputs as well
as the 2-wire intercom lines. This means that the auxiliary inputs and outputs cannot be used for other
purposes. Since these inputs and outputs are not available, ISO+ operates differently in this configuration.
Only the Master is configured for Mstr: 2-Wire ISO+ 1 Slave or Mstr: 2-Wire ISO+ 2 slvs. The Slaves are
left as Slave1 (2): 2-Wire. As soon as the Master is set for this mode, the local headset switches and LED’s
are disabled and the AUX wired status LED lights. An external 4-wire interface (with appropriate levels) can
then be connected to the front panel headset connector. The headset amplifier and microphone preamp are still
used. Therefore, the audio levels may need to be matched to the 4-wire line through external devices.
To set the system up for 2-Wire Distributed operation, configure the Master base as either Mstr: 2-Wire or
Mstr: 2-Wire ISO+ (with the appropriate number of Slaves). Then configure the Slaves as Slave1 (2): 2-Wire.
NOTE: Be sure to save settings separately on the Master and Slave bases.
Connect audio cables to the auxiliary inputs and outputs as described for Aux Distributed set up. Connect
2-wire lines between the bases as needed. Two lines are required if Clear-Com lines are used, but only one is
needed for RTS. If the system is to be connected to a hardwired intercom system through the 2-wire interface,
do that as well. Be sure that all bases are configured for the same type of 2-wire line (Clear-Com or RTS).
If no hardwired system is to be used or the hardwired system uses the 4-wire interfaces, it will be necessary
to terminate the 2-wire lines. External 200-Ohm terminators may be used or the line may be terminated
internally on the Master. To do this, remove the base station cover and move the jumpers at JP4 and JP5 to
short pins 1 and 2. Be sure to restore them to their original positions before connecting the base to an
existing 2-wire system. With a 4-wire system, it will also be necessary to connect the 4-wire lines (outputs
only) of the Slave bases to the intercom system.