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3Com Router 5000 and Router 6000 v2.41
Module Guide
Chapter 3
Multifunctional Interface Modules (Router 5000)
3-26
The synchronous serial interface can work in either DTE or DCE mode. Two directly
connected devices must work as DTE and DCE respectively. The DCE provides clock
synchronization and specifies the communication rate, whereas the DTE accepts
clock synchronization and communicates at the specified rate.
The router normally works as a DTE. To identify whether the equipment connected to
the router is DTE or DCE, refer to the manual shipped with the equipment.
II. Speed and transmission segment of synchronous/asynchronous serial
interface
In different operating modes, the synchronous/asynchronous serial interface supports
different electric signal specifications and baud rates. In addition, the maximum signal
transmission segment depends not only on the specified baud rate but also on the
selected cable. The following table shows how the cable type, baud rate, and the
maximum signal transmission segment related to each other.
Table 3-16 Speed and transmission segment of the V.24 (RS232)/V.35 cable
V.24 (RS232) V.35
Baud rate (bps)
Max. transmission
segment
Baud rate (bps) Max. transmission segment
2400 60 m (196.9 ft.) 2400 1250 (4101 ft.)
4800 60 m (196.9 ft) 4800 625 m (2050.5 ft.)
9600 30 m (98.4 ft.) 9600 312 m (1023.6 ft.)
19200 30 m (98.4 ft) 19200 156 m (511.8 ft.)
38400 20 m 65.6 ft.) 38400 78 m (255.9 ft.)
64000 20 m (65.6 ft) 56000 60 m (196.9 ft.)
115200 10 m (32.8 ft.) 64000 50 m (164 ft.)
–– –– 2048000 30 m (98.4 ft.)
Note:
When a V.24 cable is used, the baud rate of the FIC-SA in synchronous mode shall not exceed 64 Kbps.
3.7.2 Interface Attributes
The following table describes the interface attributes of the FIC-SAE: