Motorola iDEN Site Controller System Manual page 126

Chapter 4 Installation
Intercabling Connections
CAUTION
4-60
THE SURGE ARRESTOR INSTALLED ON THE SITE CONTROLLER SIDE
OF THE SMARTJACK WILL ATTEMPT TO CLAMP THE 48VDC TO
APPROXIMATELY 8VDC, WHICH WILL DISRUPT SITE CONTROLLER
OPERATION. IF THIS CONDITION CONTINUES, THE SURGE
ARRESTOR MAY BE DAMAGED AND ISOLATED FROM THE REST OF
THE CIRCUIT. THE SITE CONTROLLER MAY START OPERATING.
PROPER OPERATION MAY BE OBSERVED, BUT THE SURGE
ARRESTOR WILL NO LONGER PROVIDE SURGE PROTECTION. THIS
CONDITION IS NOT IMMEDIATELY APPARENT BUT IS EASILY
DETECTED WITH A VOLTMETER.
THE SITE CONTROLLER NETWORK CONTAINS A BUILT-IN SURGE
ARRESTOR. IF 48VDC IS PRESENT, THE T1/E1 SIGNAL WILL BE
DISRUPTED, PREVENTING PROPER OPERATION. IF APPLICATION OF
48VDC CONTINUES, THE SITE CONTROLLER'S POWER LINE CROSS
PROTECTION CIRCUITRY ACTIVATES. AS LONG AS THE 48VDC IS
PRESENT, THE CIRCUIT REMAINS OPEN. REMOVING THE 48VDC
CAUSES THE CIRCUIT TO CLOSE. NORMAL OPERATION MAY RESUME
AS LONG AS THE 48VDC IS NOT PRESENT.
Loopback/All Ones
I
Upon loss of the signal, some smartjacks have the option of going into
loopback, instead of transmitting all ones. The site controller is
provisioned to provide an ESF framed, all-ones keep-alive signal when not
call processing.
Many Smartjacks use pulse detection to indicate LOS. However, the site
controller does not transmit anything when not powered, thus triggering
the transmit LOS circuitry. To maintain the network connection when the
EBTS is off-line, iDEN operators prefer an "all ones" Smartjack
configuration.
Gen 3 Site Controller System Manual
CAUTION
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68P80801E30-A 5/1/2002