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Digicom LCM16P User Manual

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LCM16P
LCM16PR
USER'S MANUAL

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Summary of Contents for Digicom LCM16P

  • Page 1 LCM16P LCM16PR USER'S MANUAL...
  • Page 3 The contents of this booklet may be modified without prior permission. Every possible care has been taken in testing and putting together all the documentation contained in this booklet, however DIGICOM can not take any responsibility brought by the use of this booklet.
  • Page 4 INDEX PRECAUTIONS 1. INTRODUCTION 1.1. PRODUCT FEATURES 1.2. TECHNICAL CHARACTERISTICS 1.2.1. DTE-DCE digital interface 1.2.2. Data input 1.2.3. Clock signal characteristics 1.2.3. RTS/ CTS circuits 1.2.4. Asynchronous Mode 1.2.5. Analog Interface: transmission line 1.2.6. Analog Interface: receive line 1.2.7. Receive time base (synchronous mode only) 1.2.8.
  • Page 5 4.6. TEST DURING LOOP DECLARATION OF CONFORMITY TABLES INDEX Tab.: 1.1. CCITT V24 INTERFACE SIGNALS USED IN LCM16P AND LCM16/PR MODEMS Tab.: 1.2. DELAY TIMES RTS/CTS Tab.: 1.3. DCD DELAY TIME. Tab.: 1.4. CONNECTION DISTANCE WITHOUT THE EQUALIZER Tab.: 1.5. CONNECTION DISTANCES WITH EQUALIZER PICTURES INDEX Fig.: 1.1.
  • Page 6 PRECAUTIONS The following installation rules should be respected in order to have the best working order of the equipment an user’s safety. Enviromental Conditions For all devices: ENVIROMENTAL RELATIVE TEMPERATURE HUMIDITY from -5 to + 45°C from 20 to 80% n.c. Avoid rapid changes of temperature and humidity (0,03°C/ [min.]).
  • Page 7 ITALY - 21010 Cardano al Campo VA Via Alessandro Volta 39 Tel. 0331/702611 - Fax 0331/263733 - Fax +39/331/263733 Tel. +39/331/702611 http://www.digicom.it ROMA 00194 Roma Via Dei Colli Della Farnesina 72 Tel. 06/36300015 - Fax 06/3293695 Tel. +39/6/36300015 - Fax +39/6/3293695...

  • Page 8: Product Features

    INTRODUCTION 1.1. PRODUCT FEATURES The digicom LCM16P is a baseband modem in table top or rack version. It is possible to use LCM16 modem in systems of dedicated point to point, multiple point and tandem two or four wire lines.
  • Page 9 1.2.2. Data input Synchronous mode operation speed 19200, 14400, 9600, 7200, 4800, 3600, 2400, 1800, 1200, 900, 600, 450, 300, 225 bit/s. It is possible to change speed by the internal dip switches. Asynchronous mode operation speed 19200, 14400, 9600, 7200, 4800, 3600, 2400, 1800, 1200, 900, 600, 450, 300, 225 bit/s, with extension to the following speeds: Predisposition...
  • Page 10 (CCITT LOOP 2LOCAL) <----- - 12 volt From -----> External transmission clock <----- Active Loop NOTE: 1, 11, 12, 13, 14, 16, 19, 23 pins are not connected. Tab.: 1.1. CCITT V24 INTERFACE SIGNALS USED IN LCM16P AND LCM16/PR MODEMS...
  • Page 11 1.2.3. Clock signal characteristics (Only for synchronous mode operation) Signal type Square wave with negative edge on the center of data bit. Data change on the positive edge. Frequency Equal to selected speed. It has a precision of ± 50 ppm in the range of above-mentioned tempera- ture.
  • Page 12 1.2.4. Asynchronous Mode As described in the following table, it is possible to set the number of data, stop, and start bits by means of the dip switches: START bit DATA bit STOP bit 1.2.5. Analog Interface: transmission line Impedance 600 ohm or 150 ohm selected through jumpers.
  • Page 13 C109 (DCD) Threshold -40 dBm or -30 dBm, selected through a jumper. Equalizer Statistic type, enabled by a jumper, optimized for the following speeds: 1200, 2400, 4800, 9600, 19200 bit/s or 900, 1800, 3600, 7200, 14400 bit/s. 1.2.7. Receive time base (synchronous mode only) Signal type Square wave with negative edge on the center of data bit.
  • Page 14 1.2.9. Tests Available Loops All loops can be run either from the user interface or from pushing buttons on the frontal panel. The loop functions are available for point to point, multi-point and tandem networks. Test Enable In local loop 3 and remote loop 2, a push of the test button allows to send data (BERT 511) to verify the correct functionality of the net.

  • Page 15: Functional Block Diagram

    1.2.11. Line connection The line is connected thorough a RJ11 connector. In a two-wire connection, it is mandatory to use the receiver pins (RX). 1.2.12. DTE connection Standard female 25 contact connector in accordance with ISO 2110 standard. 1.3. FUNCTIONAL BLOCK DIAGRAM Look at the schematics indicated in figure 1.1.
  • Page 16 1.3.3. Line Interface Before being sent in line, the modulated signal is “shaped” and filtered in order to limit the emitted spectrum band. The telephonic line is coupled using two transformers that guarantee a 1500 Volt isolation between the line leads and the internal circuits. To compensate the jitters introduced by the line it is possible to insert a compromise equalizer either on the transmission or on the receive circuits.
  • Page 17 Fig.: 1.1. FUNCTIONAL BLOCK DIAGRAM...

  • Page 18: Transmission Circuit

    1.4. TRANSMISSION CIRCUIT 1.4.1. Digital section An internal logic regulates the transit of data to/from the Digicom ASIC, then data transit through the A/S converter. The ON position of dipswitch DSC3 activates the synchronous mode. The OFF position of dipswitch DSC3 activates the asynchronous mode.
  • Page 19 It is possible to activate a time out function on the C105 circuit. The time out function, if active (dip switches DSE 2-3), allows to block the carrier for a time of 64 or 128 Kbit/ time. This function is very useful in multi-point nets, where a continuous communication from a peripheral station to the master would cause a block in communication with all the other stations connected to the net.

  • Page 20: Receiver Circuit

    With C105 ON, the output impedance is 600 or 150 ohm, while with C105 OFF the output impedance has a value higher than 10 Kohm. The line transformers assure galvanic isolation (1500 Vrms) and adaptation between balanced line circuits and unbalanced internal circuits. Jumpers U2 and U8 select two different values of transmission impedance: 150 ohm (for speeds higher or equal to 2400 bit/ s) and 600 ohm (for speeds lower than 2400 bit/ s).

  • Page 21: Power Supply

    V24 interface. 1.6. POWER SUPPLY The LCM16P modem in its tabletop version uses three values of DC power 12V, +5V, obtained by the main power. The power supply transformer and the AC high voltage bipolar switch are mechanically protected.
  • Page 22 Test activation occurs after sending a particular sequence of characters from DTE. The LCM16P modem is able to select a set of 32 addresses by the DSA dipswitches. When the remote loopback is activated (driving ON the C140 circuit or pushing the LOOP2R button), a communication between the two modems is set up.
  • Page 23 Only in multi-point or tandem configuration, it is possible to request a local loop 3 (line loop on local modem) from the local modem, asserting the C140 interface signal and sending the same address set by DSB. Fig.: 1.3. BLOCK DIAGRAM...
  • Page 24 THIS CHAPTER IS INTENTIONALLY BLANK...
  • Page 25 OPERATION MODE 3.1. DEVELOPMENT AND ACCESSORY LCM16P is available in two models: LCM16P (code 8D1678) table-top version The modem is contained in a metallic envelope. It is directly supplied from the 230 Volt main power supply. LCM16PR (cod. 8D1726) rack version The modem is a card to be inserted in a chassis 4 unit high (RMC23P, RMC27 and RMC28).
  • Page 26 3.2. COMMAND AND MESSAGE DEVICES Back panel Back panel of LCM16P: main power switch. Frontal panel Green “PWR” led. It lights ON when the device is supplied. Red “C106” led (Clear To Send). It lights ON when the CTS signal is ON.
  • Page 27 It enables the test pattern when the modem is in LOOP 3 and LOOP 2R. NOTE: It is possible to enable or disable the buttons on the frontal panel through the DSE1 dipswitch. Fig.: 3.1. LCM16P FRONTAL VIEW Fig.: 3.2. LCM16P BACK VIEW...

  • Page 28: Installation Procedure

    Take out the card from the packing and clean it from protection material. Check if there are any damages to the device. If yes, contact DIGICOM for the necessary provisions. Put the rack or the tabletop modem in the chosen place for installation and proceed to the connections according to the following chapters.
  • Page 29 3.4. LCM16P AND LCM16PR PREDISPOSITION In the LCM16P and LCM16PR modems, there are jumpers to configure the analog section and dipswitch to configure the digital section. Look at the modem topography to see the position of jumpers and dip switches.
  • Page 30 3.4.1. Functional Description DSA 1-2-3-4-5 Selection of address for activation of LOOP2R Address OFF OFF OFF OFF OFF 01 OFF OFF OFF OFF 03 OFF ON OFF OFF OFF 05 OFF OFF OFF 07 OFF OFF ON OFF OFF 09 OFF ON OFF OFF 0B OFF ON...
  • Page 31 DSA 67 Selection of network type for V54 operations Network type OFF OFF V54 disabled OFF V54 in TANDEM mode OFF ON V54 in MULTI-POINT mode V54 in POINT TO POINT mode DSA 8 Selection of V54 recognition sequence (128 or 256 contiguous bits) OFF The receive modem recognizes a 256 contiguous bit sequence.
  • Page 32 DSB 1-2-3-4-5 Selection of receiver address for LOOP2R activation Address OFF OFF OFF OFF OFF 01 OFF OFF OFF OFF 03 OFF ON OFF OFF OFF 05 OFF OFF OFF 07 OFF OFF ON OFF OFF 09 OFF ON OFF OFF 0B OFF ON OFF OFF 0D OFF OFF 0F...
  • Page 33 DSB 6 Selection of V54 timer loop (5 or 22 minutes) The remote loopback 2 ends 20 minutes after the request of activation from the local modem. The remote loopback 2 ends 5 minutes after the request of activation from the local modem. DSB 7 control of C140 signal C140 disabled: it is not possible to activate LOOP2 from DTE...
  • Page 34 DSC 3 Selection of synchronous or asynchronous mode The modem functions in asynchronous mode. The modem works in synchronous mode. DSC 4 Selection of extended frequency range in asynchronous mode Extended range of frequency. Normal range of frequency. DSC 5-6-7-8 Selection of line speed BAUD RATE 300Bit/ sec...
  • Page 35 DSD 123 Selection of C105/ C106 delay or of C105 fixed ON RTS/ CTS delay 0 bit-time OFF ON 16 bit-time OFF ON 32 bit-time OFF OFF ON 64 bit-time OFF 128 bit-time OFF ON OFF 256 bit-time OFF OFF 512 bit-time OFF OFF OFF C105 fixed ON (always active) DSD 4 Selection of modulation type...
  • Page 36 DSE 1 Enable/disable the buttons on the frontal panel All the buttons on the frontal panel are disabled. All the buttons on the frontal panel are enabled. DSE 2 Time-out enable/disable The time-out is disabled. The time-out is active for a time equal to that selected with DSE- 3 dipswitch.
  • Page 37 Tx impedance and Rx 150 Ohm: U2- U8- U12- U15= 2-3 Note: The jumpers that are not listed in the table (U1, U5, U10, U11 and U14) must not be considered by user (they are used as test point by Digicom personnel).
  • Page 38 JB 1 JA 1 DS-E DS-C DS-B DS-D DS-A Fig.: 3.6. LCM16P TOPOGRAPHICAL VIEW...
  • Page 39 It is possible to use the LCM16PR digicom modem in the RMC23/23P rack and in the new RMC27/RMC28 rack. The U21, U22, U23 jumpers must be set in the following positions depending on the type of rack in which the devices are inserted...
  • Page 40 DIAGNOSTIC 4.1. INTRODUCTION The LCM16P and LCM16PR modems have the possibility to test the correct functionality in line. The possible tests are loop 3 (line or analog loop), local loop 2 (interface or digital loop), remote loop 2 (remote digital loop), all according to CCITT V54 standard.
  • Page 41 LOCAL LOOP 2 ACTIVATION If you want to activate this loop, press the button LOOP2 placed on the frontal panel of LCM16P or LCM16PR. In these conditions, the data interface is excluded. The data present on the C104 circuit are transmitted back on the C103 internally to the modem and then transmitted in line to the remote modem.
  • Page 42 Set ON the C140 signal of the local modem. It starts sending the loop 2 sequence to all the peripheral modems present on the net. Then it sends the address of the remote modem to be forced in loop. Push the LOOP2R button on the frontal panel. For multi-point nets, first select the desired remote modem address (DSB dipswitches), and then push LOOP2R button.
  • Page 43 4.5. TANDEM CONFIGURATION EXAMPLE Fig.: 4.4. TANDEM CONNECTION + MULTI- POINT In the example, activating the loop procedure using C140 circuit from the modem it is possible to set up the following loops: If you send the address of modem A (01), the modem A is forced in Loop 3. If you send the address of modem B (01), the modem Bis forced in Loop 3.
  • Page 44 Clock source: The clock source for modems A, D, E, F depends on DTE clock configuration (Internal or External) External clock for modems B and C. C105 and C108 control: C105 and C108 for modem A, D, E, F depend on DTE configuration (forced or controlled).

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