Black Box ME444AE-R3, ME445C-X.21, ME445C-35, ME444A-R3 Applications, Point-to-point application

CHAPTER 2: Introduction

2.2.5V.54 DIAGNOSTICS

V.54 loops are activated manually with the front-panel buttons, or through the DTE interface. The buttons and the DTE interface can be enabled or disabled separately by jumpers J7 and J8 (shown in Figure 3-1 and described in Table 3-1).

When you use the line driver as a tail-end to a digital network, the V.54 DLY jumper in the modems located close to the network should be set to ON to prevent multiple loopbacks. The delay switch is used to prevent the last modem from receiving the complete V.54 data sequence and, in turn, being induced into a loop.

2.2.6TEST-PATTERN GENERATOR AND RECEIVER

This feature allows for easy and quick testing of the local modem as well as the communication link. When the PATT button on the front panel is pressed, the circuit sends and checks a standard 511-bit pseudo-random pattern. If the modem encounters errors, the ERR LED remains ON or blinks.

The test can be carried out in local analog loopback, in remote digital loopback, or in normal point-to-point operation opposite a remote line driver modem. Press the PATT pushbutton on the remote unit or connect a Bit Error Rate Tester that uses the standard 511-bit pattern.

2.3 Applications

The diagrams on this page and the following pages illustrate the line driver operating in various applications.

4-wire

Up to 11.8 mi. (19 km)

	256-kbps	256-kbps
		Line Driver
	Line Driver
		19.2 to
		256 kbps
AS/400®			AS/400

Figure 2-2. Point-to-point application.

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