3com 3C13701 User Manual

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.   

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 

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. 

 

The following table describes the interface attributes of the FIC-SAE: