Black Box LRU4240 manual QRW Pattern Test, Other Pattern Tests

Dual Trunk E1 Router

	LOOP UP REMOTE
LOCAL				REMOTE
Dual Trunk E1 Router			Dual Trunk E1 Router
DSU	CSU		E1	CSU DSU
Data	Network	WAN	Network	Data
Port	Interface		Interface	Port
		E1
	LOOP DOWN REMOTE
LOCAL				REMOTE
Dual Trunk E1 Router			Dual Trunk E1 Router
DSU	CSU		E1	CSU DSU
Data	Network	WAN	Network	Data
Port	Interface		Interface	Port
		E1

Figure 8-2 Loop Up/Down Remote Test

NOTE: The full bandwidth loop up code puts the remote Dual Trunk E1

Router in a full bandwidth network loopback.

Pattern Tests

QRW Pattern Test

Use the Quasi-Random Word (QRW) test to measure Bit Error Rates on the network. The Dual Trunk E1 Router sends a QRW pattern into the network and monitors the received E1 network signal for QRW bit errors. QRW is a good approximation of actual user data. It is also known in the industry as Quasi Random Signal State (QRSS).

This test also looks for bit errors in both E1 circuit directions when the remote system is looped up. In this case, the system transmits the QRW to the E1 network; the remote system loops it back to the Dual Trunk E1 Router which monitors the signal for errors.

You can also use the QRW code to isolate a E1 network problem to a specific transmission direction. In this case, both E1 transmission directions are monitored when the local and the remote system transmit QRW (the remote is not put into loopback).

Other Pattern Tests

Other pattern tests types are listed and described in Table 8-2.

Table 8-2 Send Test Types Descriptions

	Send Test Type	Pattern Test Description
	1:7 Pattern	Stresses the timing recovery circuits of repeaters and other intermediate equipment.
1:1		Sends alternate ones and zeros—used to test for bridge taps.
	All Ones	Used for signal power measurements.
68		SALES: 0870 90 10 750	Dual Trunk E1 Router User’s Guide