M8000 Series

RS-232 / MIL-STD-188C (Unbalanced)

Fiber Optic MicroModem

Technical Manual

See Technical Data Sheet

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www.versitron.com

Revision A

Copyright March 2002

VERSITRON, Inc.

83 Albe Drive / Suite C

Newark, DE 19702

PROPRIETARY DATA

All data in this manual is proprietary and may not be disclosed,

used or duplicated, for procurement or manufacturing purposes,

without prior written permission by VERSITRON .

WARRANTY

All VERSITRON products purchased after January 2001 carry a limited lifetime warranty against defects in material and workmanship. Purchases made prior to January 2001 are warranted for a period of one year from date of delivery. VERSITRON reserves the right to repair or, at our option, replace parts which during normal usage prove to be defective during the warranty period provide that:

1. You call VERSITRON at (302) 894-0699 or (800) 537-2296 and obtain a (RMA) Return Authorization Number. Please reference your RMA number on the outside of the box in which the item is returned.

2. Shipping charges are pre-paid.

No other warranty is expressed or implied and we are not liable for consequential damages. For repairs outside of the warranty period, the same procedure must be followed.

TABLE OF CONTENTS

SECTION 1: DESCRIPTION OF EQUIPMENT

1.1 INTRODUCTION

1.2 DESCRIPTION OF EQUIPMENT

1.2.1 Functional Characteristics

1.2.2 Physical Characteristics

1.3 SPECIFICATIONS

SECTION 2: INSTALLATION

2.1 GENERAL

2.2 SITE SELECTION AND MOUNTING

2.2.1 Signal Interface

2.2.2 User Selected Options

2.3 POWER REQUIREMENTS

2.3.1 Installation With AC Power

2.3.2 Installation With DC Power

2.4 INITIAL CHECKOUT PROCEDURE

SECTION 3: OPERATION

3.1 INTRODUCTION

3.2 STATUS INDICATORS/ALARM

3.3 Operating Controls

SECTION 4: THEORY OF OPERATION

4.1 INTRODUCTION

SECTION 5: MAINTENANCE AND TROUBLESHOOTING

5.1 INTRODUCTION

5.2 FAULT ISOLATION

List of ILLUSTRATIONS

1. OVERALL VIEW, M8000 MICROMODEM

2. INTERFACE EXTENDER CONFIGURATION

3. MODEM LINK CONFIGURATION

4. Switch Settings.

SECTION 1

DESCRIPTION OF EQUIPMENT

1.1 INTRODUCTION

This manual provides general and detailed information on the installation and operation of the M8000 Series MicroModems. Section 1 contains a general description of the equipment. Section 2 contains installation instructions. Section 3 contains operating instructions. Section 4 provides the theory of operation. Section 5 contains maintenance and troubleshooting information.

1.2 DESCRIPTION OF EQUIPMENT

1.2.1 Functional Characteristics

The M8000 modems (Figure 1) provide copper-to-fiber conversion for data transmission over fiber optic cable as interface extenders (Figure 2) or as modem links (Figure 3) for synchronous or asynchronous data. M8213 and M8223 modems are equipped with multimode 850nm LED optics and can transmit over a pair of multimode fiber cables for up to 2 Km (6,600 ft). M8214 and M8224 modems are equipped with multimode 1300nm LED optics and can transmit over a pair of multimode fiber cables for up to 8 Km (26,400 ft). M8215 and M8225 modems are equipped with single mode 1300nm LED optics and can transmit over a pair of single mode fiber cables for up to 15 Km (49,500 ft). The link is fully transparent in both directions at any data rate from 1 Bps to 100 Kbps with terminal timing or from 1 Bps to 64 Kbps with source timing. Interface control signals associated with RS-232 and MIL-188C Unbalanced standards are fully supported. This is accomplished by multiplexing the control signals along with the clock and data signals and transmitting the combined signal to the remote unit. At the remote end the combined signal is demultiplexed and applied to the interface.

1.2.2 Physical Characteristics

The M8000 modems measure 2.5 x 1.0 x 4.5in (6.35 x 2.54 x 11.43cm) (HWL). Housed in extruded aluminum, these modems are self-contained and may be mounted directly to electrical interface connectors. The M821x is a DCE unit with a female DB25 for connecting to a terminal electrical interface. The M822x is a DTE unit with a male DB25 for connecting to a modem electrical interface. ST optical connectors are standard for all models with the transmitter optic located closest to the power connector.

FIGURE 1. OVERALL VIEW, M8000 MICROMODEM

The M8000 modems require DC power for operation, with a one-pin connector for electrical input. DC power (+5 to +15 VDC) may be applied to pin 9 of the DB25 interface if host power is available. An external power adapter is available for converting AC to DC if host power or chassis power is not used. Reference Section 2.3 for more information.

A 19" standard rack mount chassis (Model MRR-16) is available for mounting and providing power for up to 16 modems (Figure 4). The MRR-16 measures 19 x 3.5 x 11.2in (48.3 x 8.9 x 28.4cm). Power transformer (Model M0004) provides DC power to the chassis from an AC power source. Two M0004 power supplies are recommended for power redundancy. The M0004 inline power supply measures 1.3 x 2.5 x 5.1in (3.33 x 6.35 x 13.02cm). The M0004 is not designed for chassis mounting but is small enough to be secured in the chassis if so desired. The M0004 supplies power to the MRR-16 chassis power bus bar. From the bus bar, power is provided to each modem by a 6" power cable (Model M0001). Please note that each modem requires a separate M0001 power cable.

FIGURE 2. INTERFACE EXTENDER CONFIGURATION

FIGURE 3. MODEM LINK CONFIGURATION

1.3 SPECIFICATIONS

Data Signal: Signal level and format conform to EIA RS-232 and MIL-STD-188C Unbalanced standards.

Data Rate: Source Timing - continuously variable from 1 Bps to 64 Kbps for synchronous or asynchronous signals.

Terminal Timing - continuously variable from 1 Bps to 100 Kbps for synchronous or asynchronous signals.

Operating Mode/Range: Full duplex or simplex operation over a fiber optic cable pair with maximum range of 2 Km (6,600 ft) for 850nm multimode, 8 Km (26,400 ft) for 1300nm multimode, and 15 Km (49,500 ft.) for 1300nm single mode.

Optical Interface:

Note: Multimode tests were performed on 62.5/125 µM fiber optic cable.

Single Mode tests were performed on 9/125 µM fiber optic cable.

Electrical Connector: DCE - DB25 female for terminal interface connections.

DTE - DB25 male for modem interface connections.

Bit Error Rate: Better than 10^-9.

Sampling Rate: 300 KHz (clock and data), 18.75 KHz (control lines). When asynchronous data is applied to control lines, there is approximately 5% jitter at a data rate of 1 Kbps.

Dimensions: 2.5 x 1.0 x 4.5in (6.35 x 2.54 x 11.43cm) (HWL)

Weight: 6 oz (0.17 kg)

Power Requirements: 115/230 VAC, 1.4 Watts, with power adapter providing 12 VDC, 1 A (Model PSAC08, US; Model PSAC09, European). If using host power, +5 to +15 VDC may be provided on pin 9 of the DB25 connector.

SECTION 2

INSTALLATION

2.1 GENERAL

This section contains information on installation and checkout of the M8000 MicroModems. Paragraph 2.2 contains general information on site selection and rack mounting. Paragraph 2.3 contains instructions for connecting M8000 modems to your system and selecting options. Paragraph 2.4 contains initial checkout procedures.

2.2 SITE SELECTION AND MOUNTING

The M8000 modem connects to the electrical interface with two hand-tightened screws. When mounting to a PC, facsimile equipment or STU III telephone, securely position the modem allowing space for the power adapter, if used. Up to 16 modems may be installed in a MRR-16 rack mount chassis (Figure 4). The MRR-16 chassis measures 19.0 x 3.5 x 11.2in (48.3 x 8.9 x 28.4cm). Power transformer (Model M0004) provides DC power to the chassis from an AC power source. Dual M0004 transformers may be installed to provide power redundancy. In this configuration, 6" power jumper cables (Model M0001) are required for each modem installed.

FIGURE 2. OVERALL VIEW, MRR-16 CHASSIS

2.2.1 Signal Interface

DCE modems have a DB25 female connector for the terminal interface connection. DTE modems have a DB25 male connector for the modem interface connection.

2.2.2 User Selected Options

An internal switch, SW1, is provided to select EIA or MIL operation (Figure 5). Default settings for SW1 Positions 1, 2, 3, 4 and 6 are OFF; Positions 5, 7 and 8 are ON. With switch position 7 in the ON position, the modem is set for EIA operation. With switch position 7 in the OFF position, MIL operation is set. By selecting EIA on one end of the link and MIL on the other, interface conversion occurs. The rest of the switches on the circuit board are for diagnostic purposes only and should not be moved by the user.

2.3 POWER REQUIREMENTS

Model M8000 modem operates either from an AC/DC power adapter or a DC power source with a DC voltage of +5 to +15 VDC. Using pin 9 of the DB25 connector, host power may be used to supply modem power. Power adapters used with the M8000 modems are Model PSAC08 (US) for 115 VAC and PSAC09 (VDE) for 230 VAC.

FIGURE 5. SWITCH SETTINGS

2.3.1 Installation with AC Power

Connect the power adapter to the modem before inserting its plug into an AC power source. There are no special tools required.

2.3.2 Installation with DC Power

DC power may be used instead of an AC transformer, if available. This requires a 2.5 mm socket with the positive on the center and common on the concentric, and providing +12 VDC at 250mA.

2.4 INITIAL CHECKOUT PROCEDURE

MicroModems contain no power on/off switch. The unit is fully operational once installed and power is applied. Before beginning operation verify the following:

• MIL/EIA switch is set for your configuration: ON for EIA, OFF for MIL. Please note that the factory setting is ON for EIA.
• Fiber cable is "crossed" (connected from transmit to receive from one unit to the other). Note that the transmitter is closest to the power connector.
• Power plug is seated fully into the MicroModem or seated firmly in the rack mount enclosure.

If a malfunction is detected during the initial checkout procedure, refer to Chapter 5 for information on isolating the malfunction in the unit.

SECTION 3

OPERATION

3.1 INTRODUCTION

This chapter contains a description of the operating controls and indicators associated with the M8000 MicroModems. Since the M8000 modem is designed for continuous and uninterrupted operation, there are no operating requirements. Once the modem is powered up it should remain in service as long as required.

3.2 STATUS INDICATORS/AUDIBLE ALARM

There are no status indicators or audible alarms associated with the M8000 modem . If these features are required, VERSITRON Fiber Optic Modem Series II (FOM II) modems offer LED indicators and other features for monitoring the circuit. Please refer to http://www.versitron.com/RS232FOM.html for additional information.

3.3 Operating Controls

The only operating control associated with the M8000 modem is an internal switch used to select between RS-232 and MIL-188C Unbalanced. Factory setting is RS-232. Further changes are not required unless the system requirements change.

SECTION 4

THEORY OF OPERATION

4.1 INTRODUCTION

Basic operation of the M8000 MicroModem is similar to a four-channel, full duplex multiplexer. The first channel is used for data. The next two channels are used for transmit and receive clock, while the fourth multiplexer channel is used for aggregated control signals. This technique provides full transparency for the link, even when both clocks originate at the modem. The modem supplies both transmit and receive clocks to which are transmitted through the link and applied directly to the terminal.

The interface control signals are processed in a similar manner. The Request to Send signal from the terminal is transmitted through the link and applied to the modem. When the modem responds with Clear to Send, it will be transmitted through the link and applied to the terminal. With this technique, the terminal will see the RTS/CTS delay established by the modem.

If a fully transparent synchronous link is not required, the clock and control paths may be used as additional asynchronous data paths. The transmit and receive clock inputs will handle data rates from 0 to 64 Kbps asynchronously; the control paths will handle data rates up to 1 Kbps with 5% distortion.

SECTION 5

MAINTENANCE AND TROUBLESHOOTING

5.1 INTRODUCTION

This chapter contains general information designed to isolate a malfunction in the M8000 MicroModem to a replaceable unit. These units are not equipped with redundancy. Therefore, a failure in one of these units would interrupt service.

5.2 FAULT ISOLATION

There are no status indicators on the modem. Therefore, you must remove the transmit fiber optic cable to verify that the unit is emitting light (transmitting). If no light is present, check Pin 9 of the DB25 connector (if being used) or check the power transformer plug to insure that it is seated correctly and power is supplied to the unit. If light is still not present, swap out transformers to check for a bad power unit.

If data is inverted on one end of the link, check the EIA/MIL switch for correct placement. The data will be inverted relative to the associated clock.

If you are still experiencing problems, please contact VERSITRON customer service for assistance at 302-894-0699 or 800-537-2296.

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