Ring Communications DXC901 - Manual (Page 5)

SEPTEMBER 2003 DIGITAL EXCHANGE CONTROLLER DXC901
B5 RING COMMUNICATIONS INC.
DXC901 - DIGITAL EXCHANGE CONTROLLER
INTRODUCTION
The Digital Exchange Controller (DXC901) interfaces the Ring Master CB901 Central Exchange
to Ring Communications' Crisis Alert System. The Network is designed to the EIA-RS485 standard
and can support 8 nodes on a total of 30 separate networks. Each device has a specific node
address in the range of 0-7, and each CB901 central has a specific network address from 1 to 30.
A DXC901 installed on the Network with one or more Digital Network Adapters (DNA100) and/or
Digital Annunciator Displays (DAD104) provides supervision and call annunciation of
preprogrammed substations. The DXC901 requires one node address on the network, usually node
0.
OPERATIONAL DESCRIPTION
Interface to the CB901 intercom central exchange is accomplished by monitoring the CB901
subscriber bus. During initialization the DXC901 will compare the real address on the bus with a
programmed table of stations (see N
ETWORK C ONFIGURATION of Chapter C - DNA100). When a
match occurs, the DXC901 will write the information into a table in RAM. When the initialization is
complete the DXC901 will block initiative and supervise the stations for calls, faults, and alarms. The
DXC901 constantly monitors the supervised stations for any type of fault, call, or alarm initiation. Any
activity from the supervised stations causes the DXC901 to transmit a message on the network to
the nodes programmed to monitor those stations. The node interprets the message and displays
or prints the appropriate information. The operator of the node can handle the information by entering
single keystrokes - all dialing is handled by the DXC901.
Events are sent out from the DXC901 to all nodes responsible for displaying the information. By
pressing the answer key at the node associated with the display line, data is sent back to the
DXC901 which dials the associated intercom call number to obtain voice contact between the
supervised substation and the master station associated with the display node.
A C ALL from a substation is generated by a positive voltage on pin 1 of the substation audio/signaling
pair lasting for a duration of 0.9 to 1.1 secs. When a C ALL from a substation is detected by the
DXC901, the calling station can be connected to a Program Channel, if programmed, by the
DXC901's DTMF dialer. A ring tone, loop tape or digital announcer connected to the appropriate
program channel can give the caller a positive audible acknowledgment of the call placed. This
action along with the illumination of the LED can meet the requirements of the Americans with
Disabilities Act (A.D.A.).
An A LARM from a substation is generated by a positive voltage on pin 1 of the substation
audio/signaling pair lasting for a duration of at least 1.1 secs. When an A LARM from a substation is
detected by the DXC901, the calling station can be connected to a Program Channel, if
programmed, by the DXC901's DTMF dialer. A ring tone, loop tape or digital announcer connected
to the appropriate program channel can give the caller a positive audible acknowledgment of the call
placed. This action along with the illumination of the LED can meet the requirements of the
Americans with Disabilities Act (A.D.A.).