Cisco 805 Router Hardware Installation Guide
How to Select a Serial Cable
A-2
DTE or DCE
There are two types of devices that can communicate over a serial interface: DCE and DTE.
A DCE provides a physical connection to a network and forwards traffic. A DTE connects
to a network through a DCE device. Typically, a DTE device is connected to a DCE device
(or vice versa) rather than another DTE device.
Check the documentation that ships with your serial device to determine if it is a DTE or
DCE device. If you cannot find the information in the serial device documentation, refer to
TableA-1. This table summarizes serial devices that can be connected to the router serial
port and whether the device is considered a DTE or DCE device. The Cisco 805 router is a
DTE device by default. TableA-2 describes the type of cable needed to connect a DTE or
DCE device to your router.
TableA-1 DTE and DCE Devices
Serial Device DTE DCE Selectable DTE or DCE1
1 These serial devices usually have a jumper, switch, or software command that selects the DTE or DCE mode.
Modems (asynchronous and synchronous) X
Channel service unit/data service unit
(CSU/DSU)
X
Multiplexers X
Termi nal s X
Routers X
Hubs X
Switches X
Access server X
TableA-2 Cable Type Needed to Connect Serial Devices
Serial Device Type Cable Type Needed
DTE DCE