17 — DNIC and 2B1Q modules
2902 MainStreet Technical Practices
17-9
May 2002 90-2906-01
17.9
Clocking (synchronous only)
Synchronous data devices require two clocking signals: one for the receive data
stream and one for the transmit data stream. The receive clock supplies timing for
receive data; the transmit clock supplies timing for transmit data. Transmit data and
receive data are defined relative to the data device configured as DTE; the transmit
clock is used by the DTE device to transmit data and by the DCE device to receive
data. Figure 17-1 shows these relationships.
Figure 17-1 Transmit and receive clocks
The two parameters for configuring clocking for synchronous transmissions are:
•
transmit clock source
•
type of synchronous clocking
Transmit clock source
When the device mode is synchronous, the clocking source between the DNIC or
2B1Q module and the attached data device is selectable.
The transmit clock can be supplied by:
•
the attached device (EXTERNAL)
•
the data circuit to which the device is attached (INTERNAL)
•
a remote source (SLAVE) (default)
The way this parameter is set depends on whether the circuit is in DCE or DTE mode.
Table 17-2 gives the transmit clock options for DCE and DTE modes.
Table 17-2 DNIC and 2B1Q clock sources
Transmit data
Receive data
DTE
data
device
DCE
data
device
Transmit clock
Receive clock
1535
Clocking source
Meaning
DCE
Internal
A baud rate generator in the DTU provides the transmit clock. The baud rate
generator is locked to system timing. INTERNAL is only available with HCM
rate adaption.
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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 ...