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X.21 DTE Cable
Description
Before selecting SA cables for a router, obtain the remote device type (including the synchronous/asynchronous mode and DTE/DCE role), and the signal standard, baud rate, and clock required for the remote device.
Structure and Pin Assignments
Figure 8-31 shows the structure of an X.21 DTE cable.
Table 8-50 lists the pin assignments of an X.21 DTE cable.
Connection
An X.21 DTE cable is connected as follows:
- The X1 connector (DB28) is connected to the SA interface card of a router.
- Connection of the X2 connector (DB15) depends on the type of the WAN link:
- If the WAN link is a digital data network (DDN) line, connect the X2 connector to an interface of a channel service unit (CSU) or data service unit (DSU).
- If the WAN link is a dial-up line, connect the X2 connector to the serial interface on a modem.
Ordering Information
Table 8-51 provides the X.21 DTE cable ordering information.