4 • Basic Application Configurations
Model 3086 G.SHDSL Integrated Access Device User Guide
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Serial Port
Connecting the 3086 serial port to a DCE
V.35 interfaces. The V.35 interface in the 3086 is wired as a DCE, no DTE configuration is possible. If the
equipment that the 3086 is connecting to locally does not have the option for DTE configuration, a tail-circuit
cable will be required (this cable is available from most datacomm supply vendors). The tail-circuit cable will
cross most interface signals, so that the DCE interface of the 3086 and the DCE interface of the third party
equipment can function properly. Please be aware that some third party equipment will not be able to work
properly in DCE to DCE configurations even when using a tail circuit cable (please refer to your third party
equipment user manual for information on DCE-to DCE operation). The 3086 requires a cable with a male
M/34 or male DB-25 connector.
X.21 interfaces. The Model 3086’s X.21 interface configuration can be modified, by the user, as DCE (factory
default) or DTE, via an internal jumper board. When the local third party equipment is configured as DCE,
the Model 3086 X.21 serial port can be configured as DTE, and a regular straight through cable can then be
used. Do the following to configure the X.21 port as a DTE:
1. Open the 3086’s case by inserting a screwdriver into the slots and twist the screwdriver head slightly. The
top half of the case will separate from the lower half of the case (see Figure 6). Take caution not to damage
any of the PC board mounted components.
Figure 6. Case being opened with screwdriver
