Loopback Plugs For Testing Switch Interfaces; Test Facility - Allied Telesis Rapier 16fi Hardware Reference Manual

Hardware Reference
C613-03020-00 REV K

Loopback Plugs for Testing Switch Interfaces

Loopback plugs are used in conjunction with the Test Facility software to test
the physical interfaces on the switch and some PICs (see the "Test Facility"
section beginning on page 22 of this Reference, and the Test Facility chapter of
the Rapier Series Switch AlliedWare™ Operating System Software Reference). The
purpose of a loopback plug is to connect the output pins on the interface to the
input pins so that any data transmitted over the interface is looped back and
received at the same interface.
Gigabit copper interfaces cannot be looped back. Loopback plugs can be used
only in conjunction with 10/100 Ethernet interfaces.
On interfaces with control signals, these are also looped back. The data
received on the interface is compared with the data transmitted to determine
whether or not the interface is functioning correctly. In order to produce a
comprehensive test report for the interface being tested, most tests performed
by the Test Facility require a loopback plug to be inserted.
Some interfaces (e.g. synchronous ports) require a specially built external
testing device (available from your Authorised Allied Telesis distributor or
reseller) to be used in conjunction with the Test Facility.
Figure 22: Ethernet twisted pair (TP) loopback plug
Twisted Pair (TP) Loopback Plug (RJ45 connector)
TX+ 1
TX- 2
RX+ 3
4 Not
5 connected
RX- 6
Not
7
connected
8
•Not

Test Facility

This section introduces the Test Facility. The Test Facility is built into all Rapier
Switch software. For detailed information on operating the Test Facility, see the
Test Facility chapter of the Software Reference.
The Test Facility is designed to test the switch's physical interfaces. Testing
should not be performed while the switch is operational as the presence of a
loopback plug may cause feedback of network traffic. Also, any interfaces
being tested are dedicated to the Test Facility. The Test Facility can be thought
of as a specialised interface module like PPP or Frame Relay.
The Test Facility will not test Ethernet interfaces on AT-AR026 PICs.
8 7 6 5 4 3 2 1
Switch end view
of plug
RTPLOOPsw
31