3Com 3C13886 Installation Guide - Page 70

3Com Router Module Guide Chapter 3 Multifunctional Interface Modules 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: 3-26