19 — X.21 and V.35 DCMs
19-12
2902 MainStreet Technical Practices
90-2906-01 May
2002
19.10
Multidrop data bridge
In a multidrop data bridge, several broadcast destination circuits (called slaves) take
turns using the same bandwidth to communicate with one broadcast source circuit
(called the master); for example, several terminals would take turns communicating
with a host computer. The master device controls the use of the shared bandwidth by
polling each slave in turn. Figure 19-3 shows a multidrop data bridge.
Figure 19-3 Multidrop data bridge
To create a multidrop bridge, two components are needed: a data interface that
supports the multidrop function and a multidrop data bridge. The 2902 MainStreet
unit supports the multidrop interfaces but does not provide the multidrop data bridge.
One way to use a 2902 MainStreet unit in this type of application is in conjunction
with a 3600 MainStreet Multiservice Bandwidth Manager containing a Sub-Rate
Interface module (SRM).
Master and slave circuits must be configured with the same starting data position and
transport bandwidth (see chapters 21 and 22). To facilitate this, the 2902 MainStreet
system automatically sets the master circuit configuration to full duplex and
signaling off, and the slave circuit configuration to half duplex and signaling off.
These settings allow you to overlap the position of the data from these circuits.
For circuits in a multidrop data bridge, if the circuit is configured as gender DCE, the
DCD control signal must be forced on. If the circuit is configured as gender DTE, the
RTS control signal must be forced on.
Do not use the copy adjust function when configuring circuits that are to be part of
the same multidrop data bridge.
X.21 circuits
Multidrop data bridge is not supported by X.21 circuits.
V.35 circuits
Each data circuit is designated as one of the following:
•
master (MASTER)
•
slave (SLAVE)
•
not part of a multidrop data bridge (DISABLE)
Slave
devices
Master
device
Branch
circuits
Aggregate
circuit
2285
Polling
Responding
Multidrop
data bridge
Summary of Contents for MainStreet 2902
Page 1: ...2902 MainStreet Network Termination Unit Release 1 0 H T E C H N I C A L P R A C T I C E S ...
Page 40: ...3 Mounting the unit 3 8 2902 MainStreet Technical Practices 90 2906 01 May 2002 ...
Page 50: ...4 Ground and power connections 4 10 2902 MainStreet Technical Practices 90 2906 01 May 2002 ...
Page 68: ...6 Connecting to the network 6 4 2902 MainStreet Technical Practices 90 2906 01 May 2002 ...
Page 90: ...7 Connecting to data devices 7 22 2902 MainStreet Technical Practices 90 2906 01 May 2002 ...
Page 108: ...10 Node management 10 10 2902 MainStreet Technical Practices 90 2906 01 May 2002 ...
Page 150: ...14 CPSS 14 6 2902 MainStreet Technical Practices 90 2906 01 May 2002 ...
Page 218: ...20 Codirectional DCM 20 6 2902 MainStreet Technical Practices 90 2906 01 May 2002 ...
Page 234: ...22 HCM rate adaption 22 10 2902 MainStreet Technical Practices 90 2906 01 May 2002 ...
Page 246: ...23 Cross connecting circuits 23 12 2902 MainStreet Technical Practices 90 2906 01 May 2002 ...
Page 254: ...24 Visual indicators 24 8 2902 MainStreet Technical Practices 90 2906 01 May 2002 ...
Page 266: ...25 Alarms 25 12 2902 MainStreet Technical Practices 90 2906 01 May 2002 ...
Page 278: ...26 System diagnostics 26 12 2902 MainStreet Technical Practices 90 2906 01 May 2002 ...
Page 298: ...27 Loopbacks 27 20 2902 MainStreet Technical Practices 90 2906 01 May 2002 ...
Page 332: ...Glossary GL 8 2902 MainStreet Technical Practices 90 2906 01 May 2002 ...
Page 343: ......
Page 344: ... 2002 Alcatel All rights reserved 90 2906 01 95 1820 01 00 C ...