Intercall 600/700 Installation & Operation Guide Issue 4.27 Page 17 of 78
Installation Guide.
System Concepts.
Both the Intercall 600 and Intercall 700 systems are fully addressable and network devices only require a connection to
the common “Network” to operate. The Intercall 600 system uses a two core network for power and signals, while the
Intercall 700 audio system uses a four core network, one pair for power and signal and the other pair for audio. All
units are fitted with a positive (+) and negative (-) terminal and Intercall 700 audio devices have additional (a) and (b)
terminals for the audio pair.
‘Network Devices’ (Call Points, LCD Displays, Overdoor Lights etc) connect to the ‘Network’ which proves all power.
The system may be configured using a PC or Laptop Computer which connects to the L717 Power Supply.
As can be seen on page 3, several Intercall 600 and Intercall 700 network devices may be used on either systems. In
addition, it is not necessary to have the audio feature on an entire Intercall 700 system, for example L722 Non Audio
Call Points may be used within the bedrooms while Audio Call Points and Audio Displays are used elsewhere on the
system. To reduce audio interference and costs, we recommend that the network audio pair is only run to the parts of
the system where the audio feature is required.
As with all systems of this nature, the integrity of the network cabling is paramount to the performance and reliability
of the system. Excessive cable volt drop must be avoided and to achieve this we recommend the use of a heavier
“Spine” cable between Power Suppl(ies) and to Junction Units, then lighter “Spur” cables from the Junction units,
taking in the network devices. The network output from the power supply runs at 13.8V and the network devices will
operate down to 10 Volts permitting a 3.8v maximum volt drop along the network cables to the furthest device.
We only recommend the use of FJB units, which have fused outputs for the wiring of individual sections of the system.
Generally, one FJB would be located on each floor on wing of the establishment, with the Spine Cable connecting them
back to the Power Supply Units.
Understanding “Current Units”.
The amount of volt drop experienced in each length of cable depends on the size of the cable and the total amount of
current drawn by the network devices attached to it. To simplify the cable run calculations, we have given each network
device a ‘Current Unit’ value, which reflects the amount of current drawn by that unit. The following limits apply: 1.
The absolute maximum length of each spur from the FJB 2. The maximum number of ‘Current Units’ per spur
from the FJB. 3. The spine cable is also limited to a maximum length per system.
Network Cable for Intercall 600 and Intercall 700 Non speech Installations.
Use a 2 core non screened minimum 0.75mm
2
(24/0.2) cable for the network ‘Spine’ between the power supplies and
to the FJB’s and 4 or 6 core non-screened stranded security alarm cable 0.22mm
2
(7/0.2) for the network spur outputs
from the FJB.
Network Cables for Intercall 700 speech Installations.
We recommend 2 core non screened minimum 0.75mm
2
(24/0.2) and Belden 8760 for the network spine and Belden
8723 for the network spur outputs from the FJB.
Belden 8760 is a single pair cable, connect to the (A) and (B) terminals with the screen drain wire connected to (-
) and use 2 core the 0.75mm
2
non screened for the (+) and (-) connections.
Belden 8723 is a two pair individual screened cable. Use one pair for the (+) & (–) & one pair for the (A) & (B).
Connect the screen drain wire to the Network (–) terminal.
Belden cable (or equivalent) is available from
Commtech Communications www.commtechcomm.com
Phone +44(0)1254 232638 Fax +44(0)1254 301197
or other specialist suppliers.
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