Black Box LDM-MR128 User Manual
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Black Box LDM-MR128 User Manual

Black Box LDM-MR128 User Manual

256-kbps v.35 line driver
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JULY 2000
ME444A-R3
ME444AE-R3
ME444A-530-R3
ME444AE-530-R3
256-Kbps V.35 Line Driver
(LDM-MR128)
CUSTOMER
Order toll-free in the U.S. 24 hours, 7 A.M. Monday to midnight Friday: 877-877-BBOX
SUPPORT
FREE technical support, 24 hours a day, 7 days a week: Call 724-746-5500 or fax 724-746-0746
Mail order: Black Box Corporation, 1000 Park Drive, Lawrence, PA 15055-1018
INFORMATION
Web site: www.blackbox.com • E-mail: info@blackbox.com

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  • Page 1 Order toll-free in the U.S. 24 hours, 7 A.M. Monday to midnight Friday: 877-877-BBOX SUPPORT FREE technical support, 24 hours a day, 7 days a week: Call 724-746-5500 or fax 724-746-0746 Mail order: Black Box Corporation, 1000 Park Drive, Lawrence, PA 15055-1018 INFORMATION Web site: www.blackbox.com • E-mail: info@blackbox.com...
  • Page 2 FCC AND IC STATEMENTS, TRADEMARKS FEDERAL COMMUNICATIONS COMMISSION INDUSTRY CANADA RADIO FREQUENCY INTERFERENCE STATEMENTS This equipment generates, uses, and can radiate radio frequency energy and if not installed and used properly, that is, in strict accordance with the manufacturer’s instructions, may cause interference to radio communication.
  • Page 3 128-KBPS V.35 LINE DRIVER (LDM-MR128) NORMAS OFICIALES MEXICANAS (NOM) ELECTRICAL SAFETY STATEMENT INSTRUCCIONES DE SEGURIDAD 1. Todas las instrucciones de seguridad y operación deberán ser leídas antes de que el aparato eléctrico sea operado. 2. Las instrucciones de seguridad y operación deberán ser guardadas para referencia futura.
  • Page 4 NOM STATEMENT 12. Precaución debe ser tomada de tal manera que la tierra fisica y la polarización del equipo no sea eliminada. 13. Los cables de la fuente de poder deben ser guiados de tal manera que no sean pisados ni pellizcados por objetos colocados sobre o contra ellos, poniendo particular atención a los contactos y receptáculos donde salen del aparato.

  • Page 5: Table Of Contents

    128-KBPS V.35 LINE DRIVER (LDM-MR128) Contents Chapter Page 1. Specifications ..................... 5 2. Introduction ....................7 2.1 Physical Description ................7 2.2 Functional Description ............... 8 2.2.1 Encoder Modulator ..............10 2.2.2 Modulation Timing ..............10 2.2.3 Signal Levels ................10 2.2.4 Receiver ..................

  • Page 6: Specifications

    Interfaces — Line side: Proprietary; Device side: ITU-TSS V.35 Protocol — Synchronous Internal, external (from attached device), or Clock Source — recovered (from remote LDM-MR128) None Flow Control — Operation — 4-wire, full- or half-duplex, point-to-point or multipoint Data Rate —...
  • Page 7 128-KBPS V.35 LINE DRIVER (LDM-MR128) (7) Front-mounted LEDs: PWR (power), RTS, TD, Indicators — RD, DCD, TEST, ERR (error) Connectors — (2) Rear-mounted: (1) 34-pin M-block female, (1) 5-position terminal block Leads/Signals Supported — See Table 3-2 on page 25 Power —...

  • Page 8: Introduction

    The 128-Kbps V.35 Line Driver (LDM-MR128) is a short-range modem for synchronous transmission—full- or half-duplex—over unconditioned lines. With a range of up to 11.8 miles (19 km), the LDM-MR128 operates at user- selectable data rates from 19.2 to 256 Kbps.

  • Page 9: Functional Description

    128-KBPS V.35 LINE DRIVER (LDM-MR128) 2.2 Functional Description This section describes the operation of the LDM-MR128’s circuit blocks, primarily the circuits required for correctly configuring the modem (see Figure 2-1 below). Figure 2-1. LDM-MR128 block diagram.

  • Page 10: Encoder Modulator

    CHAPTER 2. Introduction 2.2.1 E NCODER ODULATOR The encoder modulator receives data from the DTE, then modulates the data using the “conditional diphase modulation” technique. You can configure the encoder to operate in one of three modes: • 4-wire full-duplex (point-to-point) •...

  • Page 11: Receiver

    DTE interface. The pushbuttons and the DTE interface can be enabled or disabled separately by the ANA, REM, and SWITCH jumpers. When you use the LDM-MR128 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.

  • Page 12: Applications

    CHAPTER 2. Introduction 2.3 Applications The diagrams on this page and the following pages illustrate the LDM-MR128 operating in various applications. 4-Wire Up to 11.8 mi. (19 km) LDM-MR128 LDM-MR128 19.2 to 256 Kbps AS/400 AS/400 ® Figure 2-2. Point-to-point application.
  • Page 13 128-KBPS V.35 LINE DRIVER (LDM-MR128) V.35 CABLE V.35 CABLE LDM-MR128 LDM-MR128 V.35 REMOTE V.35 REMOTE E-SERIES BRIDGE E-SERIES BRIDGE (LB3001A) (LB3001A) 3.7 miles (6 km) at 256 Kbps using two twisted pairs of 19-gauge wire ETHERNET ETHERNET BACKBONE BACKBONE Figure 2-4. LAN application—extending the distance...
  • Page 14 CHAPTER 2. Introduction V.35 INTERFACE V.35 INTERFACE 4-WIRE TWISTED PAIR V.35 V.35 (64 KBPS) CABLE CABLE LDM-MR128 LDM-MR128 V.35 INTERFACE IBM 3274 ® S/3X CONTROLLER MAINFRAME V.35 CABLE LDM-MR128 V.35 INTERFACE IBM 3274 CONTROLLER V.35 CABLE LDM-MR128 IBM 3274 CONTROLLER...

  • Page 15: Installation

    LDM-MR128 is an ME444A-R3 model) or 230 VAC (if your unit is an ME444AE-R3). The LDM-MR128 is designed to be placed on a tabletop or bench, and is shipped completely assembled. Allow at least 36" (90 cm) of frontal clearance for operation and access for maintenance.
  • Page 16 64 Kbps 7-56 8-48 9-32 D-19.2 Enable or disable requests for V.54 digital V54 DIS loopback tests from the remote LDM-MR128. EN (enabled) Jumper Select the Transmit-carrier mode. When you CNTRL CARRIER set this jumper to “ON,” Transmit carrier is Jumper constantly ON.
  • Page 17 128-KBPS V.35 LINE DRIVER (LDM-MR128) Table 3-1. User-Configurable Options (continued) Element Function Possible Standard Settings Factory Setting Enable or disable electronic control of EN (enabled) RLB DTE* remote digital loopback testing through the Jumper DTE interface. Enable or disable electronic control of...
  • Page 18 CHAPTER 3. Installation Figure 3-1. Layout of the LDM-MR128’s printed circuit board.
  • Page 19 128-KBPS V.35 LINE DRIVER (LDM-MR128) When you have everything at least tentatively decided, take these steps to set the unit’s internal controls: CAUTION! Disconnect the unit from the power line before removing it from its housing. WARNING: HIGH VOLTAGE! Any adjustment, maintenance, and repair of the open instrument under...

  • Page 20: Installation In 19-Inch Racks

    To prepare the LDM-MR128 for rack installation, attach the two brackets to the sides of the unit. Do this by inserting screws and flat washers into the two holes at the front of each side of the LDM-MR128 (nuts are already in place inside the unit).
  • Page 21 128-KBPS V.35 LINE DRIVER (LDM-MR128) 2. Using four included screws and flatwashers for each bracket, attach the two short brackets to the vacant sides of the LDM-MR128s. 3. Slide the two LDM-MR128s’ side rails into each other, fastening the two units together.
  • Page 22 CHAPTER 3. Installation Figure 3-3. Installing two units in a 19-inch rack.

  • Page 23: Connecting Data Cables

    GND is indicated. The XMT and RCV pairs are not sensitive to polarity. Connect power and data cables to the LDM-MR128 as described in the following subsections.
  • Page 24 CHAPTER 3. Installation Table 3-2. Pinout of the LDM-MR128’s V.35 Connector SIGNAL ITU-TSS LEAD V.35 NAME (ABBREV.) CIRCUIT TYPE Frame (Protective) Ground (FGND) Signal Ground (SGND) Send Data (SD) Receive Data (RD) Request to Send (RTS) Clear to Send (CTS)

  • Page 25: Power Connection

    The fuse, and one replacement fuse, are located in the top part of the mains connector on the LDM-MR128’s rear panel. The nominal current value of the fuse is 0.125 A for 230-VAC operation or 0.25 A for 115-VAC operation.

  • Page 26: Line Connection

    The LINE connection provides an interface for the TX and RX signals between pairs of LDM-MR128s. To make this connection, attach the line wires to the terminal block on the LDM-MR128 this way: • XMT + (remote LDM-MR128) to RCV + (local unit);...

  • Page 27: Dte Connection

    ONNECTION The interface (DTE) connector provides an interface for input/output data, as well as clock and control signals, between the LDM-MR128 and a V.35 DTE or DCE. This connector is a standard 34-pin M-block (“M/34”) female. The pinout of this connector is shown in Table 3-2 on page 25.

  • Page 28: Operation

    LDM-MR128. 4.1 Controls and Indicators The front panel of the LDM-MR128 is shown in Figure 4-1 below. It contains all of the unit’s external controls and indicators: four pushbutton switches and seven LEDs. The functions of the controls are described in Table 4-1 on the next page, and the meanings of the indicators are described in Table 4-2, also on the next page.
  • Page 29 DTE when the “RLB DTE” strap is set to EN. PATT Pressing the PATT button causes the LDM-MR128 to send and receive a 511 test pattern. If errors are encountered, the ERR LED becomes steadily lit or blinks. Receive Data and Clear to Send go low. Note: The unit’s “CARRIER”...

  • Page 30: Operating Procedure

    LEDs occasionally. To turn the unit off, you must unplug its power cord from the outlet—it has no power switch. If you want to reconfigure the LDM-MR128 for a different type of operation, make very sure to unplug the unit first. After the unit is powered down, change the settings of its internal controls as necessary, following the instructions in Section 3.2.

  • Page 31: Troubleshooting

    5.2 The Bit-Error-Rate Tester (BERT) You can activate the LDM-MR128’s internal Bit Error Rate Tester in any diagnostics test in which the transmitted test pattern is looped back to the BERT for comparison.
  • Page 32 CHAPTER 5: Troubleshooting PATT PRESSED PATTERN GENERATOR PATTERN TESTER ERROR ASM-20 Figure 5-1. BERT using loops. PATT DEPRESSED PATT (DISCONNECTS DEPRESSED EXTERNAL DTE) PATTERN PATTERN GENERATOR TESTER ERROR PATTERN PATTERN TESTER GENERATOR ERROR Figure 5-2. Two LDM-MR128s doing end-to-end BERT.

  • Page 33: The Modem Self-Test

    128-KBPS V.35 LINE DRIVER (LDM-MR128) 5.3 The Modem Self-Test To verify that the LDM-MR128 itself is operating correctly, initiate the modem self-test by pressing the PATT and ANA buttons (refer to Figure 5-3 below): 1. Press ANA to start local analog loopback. Both the TEST and DCD LEDs should light.

  • Page 34: Local Analog Loopback

    4. Repeat Steps 1 through 3 at the remote site. 5. If the BERT tests show no errors, but the data echoed back to either DTE is bad, check the DTE and the cable connecting it to the LDM-MR128— one of them is faulty.

  • Page 35: Remote Digital Loopback

    Remote Loopback signal received by the LDM-MR128’s V.35 connector (Pin HH). This test involves creating an outbound loopback at the remote LDM-MR128 (see Figure 5-5 on the next page). The test checks the performance of the local and remote units and the line between them: 1.

  • Page 36: Local Digital Loopback

    Activate the local digital loopback test by pressing the DIG button on the LDM-MR128’s front panel. This test involves creating an outbound loopback at the local LDM-MR128 (see Figure 5-6 on the next page). It works the same way as if the remote operator had initiated a remote digital loopback at the remote site.
  • Page 37 128-KBPS V.35 LINE DRIVER (LDM-MR128) • Hook up an external BERT unit in place of the remote DTE; or • Use the remote LDM-MR128’s internal BERT. Press the PATT button. The ERR LED should light briefly just to confirm that the LED is working, and then the test will proceed.

  • Page 38: Calling Black Box

    If you need to transport or ship your LDM-MR128: • Package it carefully. We recommend that you use the original container. • If you are shipping the LDM-MR128 for repair, make sure you include its power cord. If you are returning the LDM-MR128, make sure you include its manual as well.

  • Page 39: Appendix: Maximum Distances

    128-KBPS V.35 LINE DRIVER (LDM-MR128) Appendix: Maximum Distances The maximum distance that a pair of LDM-MR128s can communicate across will vary depending on the data rate and the thickness (gauge) of the wires. In multipoint applications, it will also vary depending on the number of slaves on the line.
  • Page 40 © Copyright 2000. Black Box Corporation. All rights reserved. 1000 Park Drive • Lawrence, PA 15055-1018 • 724-746-5500 • Fax 724-746-0746...

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Me444a-r3Me444ae-530-r3Me444ae-r3Me444a-530-r3

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