3Com 3C13701 Installation Manual page 37

X.21 DCE cable assembly
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Figure 29 X.21 DCE cable assembly
CAUTION: The aforementioned cables are optional, so you have to order them when
purchasing the router if needed.
Connection of Synchronous/Asynchronous Serial Cable Follow the steps below to
connect the synchronous/asynchronous cable (taking the connection from WAN to
DSU/CSU as an example):
CAUTION: Do not hot swap the synchronous/asynchronous cable. Otherwise, the router
or the connected remote equipment may be impaired.
1 Check that a proper synchronous/asynchronous cable is shipped with the router.
2 Plug the DB50 connector of the cable into the interface WAN on the router.
3 Connect the other end of the cable to the CSU/DSU device. If the WAN adopts dial-up
line, connect the cable to the serial interface of the analog modem.
Connecting E1 Interface to DSU/CSU
Introduction to the E1 Interface 1E1 interface, which stands for channelized
CE1/PRI interface, is responsible for forwarding and processing E1 data flow, delivering
CE1 access and implementing ISDN PRI function. Its attributes are listed in the following
table:
Table 18 E1 interface attributes
Attribute
Connector type
Interface standard
Maximum baud rate
Matching cable
Operating mode
Function
Description
DB15
G.703, G.704
2.048Mbps
E1 75Ω unbalanced coax cable
E1 120Ω balanced coax cable
Coax connector, network interface connector, 75Ω−120Ω converter
(with BNC connector)
E1, CE1, ISDN PRI
Backup
Terminal access
ISDN PRI
Connecting Router to the WAN 37