DCB, Inc.
2949 CR 1000 E
Dewey, Illinois
61840
217.897.6600 Tel
800.432.2638 Toll Free
217.897.1331 Fax
www.dcbnet.com
The 8 DBRA card has 32 time slots for each Virtual Port, for a total of 128 time slots. Any one of
the RS232 ports can be mapped to maximum of 20 downstream endpoints (DS-0s) on a
multidrop circuit.
Mapping is a 2 step process. The first step is to map the physical RS232 ports to virtual ports,
then map the virtual ports to one or more DS-0s. The card mapping is a sub menu for the card
slot. The Virtual Port mapping is done at the AM3440 system time slot interchange (TSI)
mapping level.
The 8 DBRA card protection mode allows port/card protection on the same card, on a different
card in the same chassis, or on a different (remote) chassis.
The 8DBRA card can be used at a central host site, a midpoint remote drop location, or endpoint
remote drop location.
At a host site, backup may be:
–
To the backup ports (ports are paired 1 and 5, 2 and 6, 3 and 7, 4 and 8).
–
To a second card in the same chassis. Card slots are paired 1&2, 3&4, 5&6, etc.
–
To a second card in a different chassis at another location
At a remote drop site (downstream location), backup may be:
–
To the backup ports (ports are paired 1 and 5, 2 and 6, 3 and 7, 4 and 8).
–
To a second backup card in the same chassis
All 8 ports of the 8DBRA card can be mapped to different locations unless the card is set for 1+1
port backup. In 1+1 port backup, 1&5, 2&6, 3&7, 4&8 are paired, limiting the ports to 4 pairs.
The 8DBRA card can be used as a host end digital bridge device or an 8 port asynchronous data
card. The 8DBRA card is most useful, and is unique for its function as a host digital bridge
device, where data from a host computer attached to one of the RS232 host ports is broadcast
out to as many as 20 endpoints. At the card level, RS232 ports are mapped to Virtual Ports
(VPs). At the Time Slot Interchange (TSI) map level, the Virtual Port (VP) time slots are mapped
to DS-0s on T1/E1/FOM circuits. Therefor mapping is a 2 step process.
If a card is used as an 8 port asynchronous port card only (not for its bridging capability), each
port is mapped to a different time slot on a Virtual Port. As an 8 port asynchronous card in a
point to point application, only 8 of the 128 time slots are used. Only one Virtual Port (VP) needs
to be used.
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