H3C Technologies H3C MSR 50 - Manual (Page 251)

4-56
FIC-2SAE/FIC-4SAE/FIC-8SAE
Introduction
FIC-2SAE/FIC-4SAE/FIC-8SAE, 2-/4-/8-port enhanced high-speed synchronous/asynchronous serial
interface module, transmits, receives, and processes data on the synchronous/asynchronous serial
interface. They support both synchronous and asynchronous modes. In the former case, they support
the DTE/DCE mode.
DTE and DCE
An FIC-SA module is usually connected to an external modem for dialing purpose, where an
appropriate baud rate setting is required.
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.
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 4-48 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.)
When a V.24 cable is used, the baud rate of the FIC-SA in synchronous mode shall not exceed 64
Kbps.
Interface attributes
The following table describes the interface attributes of the FIC-SAE: