~~NOTOC~~
====== APC ======

DHD Series 52 modules communicate with each other via single CAT5 cables. These cables use the proprietary APC technology (Audio, Power, Control). Through APC, digital audio data and electrical power are transferred, as well as core-internal control data such as logic control, TFT control data, surface control data, firmware updates. This DHD-internal standard is not intended for use with third-party equipment. 

[{{ :installation:dhd-standard-system-apc-ga-1.png?nolink | //DHD standard system with GA connections and APC connections//}}]
===== Cable Specifications =====

Always use shielded CAT5, CAT5e or CAT6 Ethernet cables (at least S/UTP, F/UTP or SF/UTP) to connect modules and core devices. 

The maximum length matches current Ethernet standards and must not exceed 90 meters horizontal link plus 10 meters of patch cables. 

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**Important**\\  Length values are standard values that work for most applications. These values can differ, especially in environments with high electromagnetic interferences. 
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===== Power over Ethernet - PoE =====

Power over Ethernet (PoE) is a broader term to describe any technique of transmitting electrical power along standard twisted-pair Ethernet cabling. DHD's APC technology uses a unique PoE adoption created especially for direct connection of DHD hardware. This makes additional power adaptors for every connected module unnecessary. Because of this unique design, DHD does not allow to use any 3rd party PoE inserter. Also, it is not allowed to wire APC ports of Series 52 core devices directly to network switches. If these specifications are ignored, warranty becomes immediately void.

Please consider the following warnings:

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**Warning**\\  The PoE inserter (PPSA16U480POE) delivered by DHD for RM420-015/52-4015 cannot be used for 52-1156 (52/TX) and 52-4510! This PoE inserter delivers only 15 W. 52-1156 (52/TX) and 52-4510 need 20 W for operation. \\ \\ To connect a 52-1156 or 52-4510 module via fibre-optic cable, use a DHD Concentrator (52-7310, 52-7300). 
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**Warning**\\  Usage of **PoE+** inserters of other manufacturers is not allowed because they feed 56 V. DHD devices are designed for 48 V.
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**Warning**\\  Usage of self-made 48V feeder adaptors for feeding 48 V is not allowed and may cause serious damage to all devices.
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/*
DIE BEKANNTEN VON UNS MEIST FÜR RM420-015 / 52-4015 GELIEFERTEN PoE INSERTER KÖNNEN AUSDRÜCKLICH NICHT FÜR 52-1156 und 52-4510 VERWENDET WERDEN DA DIESE NUR 15W EINSPEISEN - BENÖTIGT WERDEN JEDOCH 20W !!!

LWL VERLÄNGERUNGEN SIND AUSSCHLIESSLICH ÜBER DHD CONCENTRATOREN MÖGLICH !!!

DIE VERWENDUNG VON (anderen) PoE+ INSERTERN IST AUSDRÜCKLICH NICHT ERLAUBT, DA DIESE 56V EINSPEISEN - UNSERE GERÄTE SIND DERZEIT NUR FÜR 48V AUSGELEGT !!! 

EVENTUELL VOM KUNDEN ANGEFRAGTE EIGENLÖSUNGEN WIE DIE EINSPEISUNG VON 48V ÜBER "BASTELADAPTER" SIND AUSDRÜCKLICH NICHT ERLAUBT !!!
 */