3Com Router 3000 Series, Manual, Page: 20 / 37

failure of the self-test operation. In such a case, contact your Service
representative.
6 Check the ON LED on the interface card faceplate. If it is green, it indicates that
the interface card is powered on. If it is off, contact your Service representative.
4-Port Synchronous/
Asynchronous Serial
MIM with X.21
Support
The 4-port synchronous/asynchronous serial module with X.21 supports the X.21,
V.35, and V.24 physical interfaces. Figure 5 illustrates the 4-port synchronous/
asynchronous serial module with X.21.
Figure 5 4-Port Synchronous/Asynchronous Serial Interface Module with X.21
Features Table 10 lists features of the
4-port synchronous/asynchronous serial module with X.21.
Table 10 Features of the 4-Port Synchronous/Asynchronous Serial Module with X.21
Attribute Description
Synchronous Asynchronous
Connector DB-28
Number of
connectors 4
Interface
standard and
operating mode V.24 V.35, X.21 RS232
DTE, DCE DTE DCE
Minimum baud
rate
(bps)
1200 1200 300
Maximum baud
rate
(bps)
64k 2.048M 2.048M 115.2
Cable V.24 (RS232) DTE cable
V.24 (RS232) DCE cable
V.35 DTE cable
V.35 DCE cable
X.21 DTE cable
X.21 DCE cable
Services
supported 1) Leased line
2) Terminal access service
1) Dialup
through modem
2) Backup
3) Async leased
line
4) Dumb terminal
access
3Com Router Release Notes for V1.20
20