18 — RS-232 DCM
18-8
2902 MainStreet Technical Practices
90-2906-01 May
2002
Figure 18-1 Transmit and receive clocks
The two parameters for configuring clocking for synchronous transmissions are:
•
transmit clock source
•
type of synchronous clocking
Transmit clock source
Table 18-2 explains the clock sources for DCE and DTE circuit genders.
Table 18-2 EIA/TIA-232 clock sources
Type of synchronous clocking
When you configure the type of synchronous clocking, you define the effect the
2902 MainStreet system has on clocks passing through it. The type can be set:
•
to the timing of the 2902 MainStreet system (LOCKED) (default)
•
to be passed through transparently (INDEPNT)
Receive clock
The receive clock on RS-232 DCMs with revision 2 DRAGA can be inverted. The
default is no inversion. Receive clock inversion can compensate for a phase shift
between the transmit clock and receive data signals, if it occurs.
Transmit data
Receive data
DTE
data
device
DCE
data
device
Transmit clock
Receive clock
1535
Clocking source
Meaning
DCE
External
The user equipment provides the transmit clock.
Slave
The circuit extracts transmit clock timing from the data stream.
DTE
Internal
A baud rate generator on the DCM provides the transmit clock. The baud rate
generator is locked to the system timing.
External
The user equipment provides the transmit clock.
Slave
The circuit extracts transmit clock timing from the data stream.
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 ...