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ASYNC/SYNC 2-WIRE SHORT-HAUL MODEMS

5.2 Calling Black Box

If you determine that your Async/Sync 2-Wire Short Haul Modem is
malfunctioning, 

do not attempt to alter or repair it

. It contains no user-serviceable

parts. Contact Black Box Technical Support at 724-746-5500; the problem might be
solvable over the phone.

Before you do, make a record of the history of the problem. We will be able to

provide more efficient and accurate assistance if you have a complete description,
including:

• The nature and duration of the problem.

• When the problem occurs.

• The components involved in the problem.

• Any particular application that, when used, appears to create the problem or

make it worse.

• The results of any testing you’ve already done.

5.3 Shipping and Packaging

If you need to transport or ship your Async/Sync 2-Wire Short Haul Modem:

• Package it carefully. We recommend that you use the original container.

• Before you ship a unit for repair or return, contact Black Box to get a Return

Materials Authorization (RMA) number, and make sure you include
everything you received with the unit when you ship it.

Summary of Contents for ME375A-R2

Page 1: ...days a week Call 724 746 5500 or fax 724 746 0746 Mail order Black Box Corporation 1000 Park Drive Lawrence PA 15055 1018 Web site www blackbox com E mail info blackbox com MARCH 1998 ME375A R2 ME375A...

Page 2: ...his own expense will be required to take whatever measures may be necessary to correct the interference Changes or modifications not expressly approved by the party responsible for compliance could vo...

Page 3: ...de ba o lavabo s tano mojado o cerca de una alberca etc 6 El aparato el ctrico debe ser usado nicamente con carritos o pedestales que sean recomendados por el fabricante 7 El parato el ctrico debe se...

Page 4: ...contactos y recept culos donde salen del aparato 14 El equipo el ctrico debe ser limpiado nicamente de acuerdo a las recomendaciones del fabricante 15 En caso de existir una antena externa deber ser l...

Page 5: ...al Controls 11 3 3 Connecting the Data Cables 16 3 4 Connecting to AC Power 17 4 Operation 19 4 1 The Front Panel Controls and Indicators 19 4 2 Power Up Normal Operation and Power Down 22 4 3 Reconfi...

Page 6: ...de 2B1Q encoding Clock Source Internal external from DTE or received from other unit user selectable Data Format 7 or 8 data bits 1 or 2 stop bits even odd or no parity user selectable Operation Line...

Page 7: ...loopback switch or signal triggerable Local digital loopback switch triggerable Remote digital loopback switch or signal triggerable Indicators 8 Front mounted LEDs PWR power RTS TD RD DCD LOS loss of...

Page 8: ...line side plus special gas diodes MTBF 75 500 hours Maximum Altitude 8000 ft 2438 4 m Temperature Tolerance 32 to 122 F 0 to 50 C Humidity Tolerance Up to 90 noncondensing Enclosure High impact plast...

Page 9: ...rates interface circuits for the terminal computer an adaptive echo canceler an automatic adaptive equalizer a modulator and a demodulator It is coupled to the telephone line through an isolation tran...

Page 10: ...f the unit so you can access it during operation and maintenance Make sure that there is at least 4 10 cm of clearance behind the unit for signal lines and interface cables 3 2 Setting the Internal Co...

Page 11: ...IT ASY DTR CNT 2STB ODD DIS 7BIT SYNC 9MS CLOCK LBT INT EXT SW7 0 0 6K 1 1 2K 2 2 4K 3 4 8K 4 9 6K 5 19 2K 6 38 4K 7 48K 8 56K 9 64K A 128K POS BAUD DIS EN RLB DIS EN LLB CHASS GND CON DIS 1 2 3 4 5 6...

Page 12: ...y OFF CNT RTS Position 7 DSR always ON or DSR ON ON DSR follows DTR OFF DTR If DIP Switch Position 6 is set to DCD The DCD signal is ON as long as the local unit is in proper synchronization with the...

Page 13: ...56 Kbps Position 9 64K 64 Kbps 64 Kbps P9 Position A 128K 128Kbps Position B 144K 144 Kbps Position C 57 6K 57 6 Kbps Position C 115 2K 115 2 Kbps Setting this dial has no effect or purpose if the uni...

Page 14: ...opback EN RLB testing with signals from Jumper the DTE 6 Chassis Tie Signal Ground to Chassis CON CON Ground Protective Frame Ground DIS CHASS_ or isolate the two grounds GND from each other Jumper On...

Page 15: ...for a type of cable that fits the bill bulk unterminated Category 5 UTP is EYN717A specify the length you want 2 Run the DTE side cable from the DTE to the A S2W SHM If your A S2W SHM is an ME375 mode...

Page 16: ...extension cord with the unit unless it also has a ground wire that runs between ground terminals at either end Once you are sure of proper grounding run the power cord from the A S2W SHM s IEC320 male...

Page 17: ...t the rear panel of the unit If this fuse blows make sure you replace it only with a fuse rated for the required current and of the specified type 0 2 A slow blow for ME375A R2 and ME376A R2 0 1 A slo...

Page 18: ...ocedures described in Chapter 3 before you attempt to operate the A S2W SHM If you have difficulty refer to Chapter 5 4 1 The Front Panel Controls and Indicators FIgure 4 1 below shows the front panel...

Page 19: ...S2W SHM to loop received data and clock signals back out of its own transmitter Data Set Ready goes low when this happens Press this button again to terminate remote digital loopback While the A S2W...

Page 20: ...the local unit receives data DCD 109 Yellow LED is steadily lit while a The local and remote A S2W SHMs are in sync and the local unit s DCD switch is set to DCD b The local and remote A S2W SHMs are...

Page 21: ...umper is set to DCD steadily lit if the local unit s DCD jumper is set to CNT steadily lit or dark depending on the status of the RTS signal from the remote unit LOS Flashing until the units synchroni...

Page 22: ...from it 3 Open the unit s cover 4 Referring to Figure 3 1 on page 12 and Table 3 1 on pages 13 through 15 set the unit s internal controls to suit the new application 5 Close the cover 6 Perform Step...

Page 23: ...d normally When you have verified this perform the tests described in Sections 5 1 1 5 1 2 and 5 1 3 in that order 5 1 1 LOCAL ANALOG LOOPBACK Use this test to check the performance of the local modem...

Page 24: ...all your DTE s supplier If you don t have a BERT unit and the DTE test indicates an error make sure the cables connecting the DTE to the A S2W SHM are securely connected If they are try swapping in kn...

Page 25: ...PATT button to have it send a test pattern through the loop Press the PATT button again to stop the test pattern 3 If Step 2 indicates a fault but Local Analog Loopback testing was successful for bot...

Page 26: ...nds a local loopback notification to the remote unit and then internally connects its receiver input to its transmitter output see Figure 5 3 below 2 The operator at the remote site can test the units...

Page 27: ...u have a complete description including The nature and duration of the problem When the problem occurs The components involved in the problem Any particular application that when used appears to creat...

Page 28: ...S Send Data B SD B from the DTE In synchronous applications the data transitions must occur on the rising edge of the transmit clock 104 3 Receive Data RD R Receive Data A RD A Serial digital data se...

Page 29: ...s signal DTR DTR when it is ready to transmit or receive If the remote unit s DIP Switch Position 7 is set to DTR the remote unit s DSR will follow reflect this signal 109 8 Received Line Signal F Rec...

Page 30: ...ceive A More commonly known as Element Timing DCE SCR A Receive Clock RXC The RSETC X Serial Clock Receive B remote A S2W SHM sends SCR B this data rate clock signal to the lccal unit which in turn pa...

Page 31: ...iption CCITT RS 232 Abbreviation for V 35 Abbreviation for V 24 Pin EIA RS 232 Pin s ITU TSS V 35 Circuit ME375 ME375 ME376 ME376 142 25 Test Mode TM KK Test Mode TM The A S2W SHM raises this signal d...

Page 32: ...mages whether based on contract tort or any legal theory RESERVED RIGHTS This document contains materials protected by copyright including information belonging to the manufacturer All rights are rese...

Page 33: ...NOTES...

Page 34: ...1000 Park Drive Lawrence PA 15055 1018 724 746 5500 Fax 724 746 0746 Copyright 1998 Black Box Corporation All rights reserved...

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