ADTRAN T1-FT1 user manual DTE Interface Loopbacks, All Ones

Chapter 1. Introduction

DTE Interface Loopbacks

The Nx56k/64k serial interface offers a DTE loopback. See

Figure 1-8.

DTE Loopback: loops all data from the DTE back towards the DTE. This loopback may be initiated by the DTE asserting the Local Loopback (LL) input on the connector or by using front panel or T-WATCH commands. The DTE (or external test equipment) must provide any test pattern in order to check the DTE interface.

DTE
Loopback	TSU
		Nx56/64
		Interface
T1	Network Interface	Nx56/64 to
		network control
	(NI)	circuit

to DTE

Figure 1-8. DTE Interface Loopback

Pattern Generation

The TSU offers four available test patterns, All Ones, 3:24, and 511 and 1:8.

All Ones

Need definition

3 in 24

The 3:24 is a stress pattern which places the maximum number of 0s in the transmitted data. This is always done over all DS0s. This pattern is used in conjunction with external test equipment to determine if the T1 line is preforming acceptably under a stress condition.

61200060L1-1 TSU User Manual 1-13