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154 CHAPTER 4: FLEXIBLE INTERFACE CARDS
DTE and DCE
An FIC-SA card 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.
n
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:
Table 108 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.)
Table 109 Interface attributes of the FIC-2SAE/FIC-4SAE/FIC-8SAE
Attribute
Description
Synchronous Asynchronous
Connector DB-28
Number of connectors 2 (FIC-2SAE)
4 (FIC-4SAE)
8 (FIC-8SAE)