Comstream cm701 manual

Use only a clean, soft cloth lightly moistened with a mild detergent solution. Wipe all equipment with a clean, soft cloth lightly moistened with water to remove the detergent solution. Page Applications Applications The CM is well suited for point-to-point satellite communications applications with data capacity requirements that change periodically.

It can be reconfigured at any time for a different data rate, code rate, or modulation type. It is also valuable for users with many different communication requirements. One CM can be software-configured for virtually any common operating mode. Page Features LCD display allowing the CM to be completely configured, monitored, and controlled from the front panel.

A remote terminal is easily connected to a rear panel port allowing the CM to be configured, monitored, and controlled with character-oriented ASCII protocol and RS electrical levels. Page Modular Architecture The CM was designed using a modular architecture which provides the following advantages: Independent functioning of each option card The CM can be customize for specific needs today and easily upgraded or expanded to meet the planned or unforeseen needs of tomorrow.

Simple, less costly sparing The most common option cards are This option card is particularly well suited to single channel per carrier SCPC star networks requiring multiple modems at the hub, SCPC demand assigned DAMA networks requiring fast acquisition and low cost, and complex networking needing additional modulators or demodulators. Two AC power cords are provided with each CM, one for North American applications and another for all international applications.

Theory of Operation Page Standard Cards This card serves as a command gateway between the user and any other cards in the CM It supports status relay output, as well as status relay sense signal inputs. The active interface is selected through commands issued through either the front panel or remote terminal. The BERT operates by preempting the user transmit data with BERT-generated data, and then monitoring the receive data to measure bit errors, block errors, etc.

This single frequency reference provides the following benefits: Reduced cost Page Modulator Operation Modulator Operation The CM is typically configured for full-duplex operation — transmitting and receiving data from the satellite. For most applications, these two paths are independent. Page Figure Cm Receive Process 8. Passes the carrier signal through a power control attenuator and is then fed to a BNC output at the rear of the CM The proprietary, digital-matched filter design allows tremendous flexibility under software control to create virtually any PSK waveform necessary to comply with open network specifications or to optimize channel performance.

Page Decoder Asics The receive clock and data are provided by the demodulator card to the data interface card across the CM backplane. All external clocks are smoothed, that is, there are no punctured clocks.

Inexpensive support of Remove option cards that are not needed The system has more than one CM installed, some of which have option receive-only and cards that are not being used. One of the CMs needs a replacement or transmit-only additional option card. Page Overview Common Configuration Issues Overview There are a number of commonly experienced system issues that arise during the design, installation, and operation of a satellite communications system.

This chapter covers the following system issues to help you better plan your system design, installation, and operation and avoid potential system issues: QPSK versus BPSK modulation Modem acquisition time reduction With careful filtering, BER performance within less than 1 dB of the theoretical limit may be achieved.

One approach to achieving this low error rate is to filter the baseband data before modulation with a Nyquist filter. BER performance In BPSK, a phase error in the reference carrier slightly reduces the signal-to-noise ratio of the data detection process, but in QPSK, a phase error quickly introduces crosstalk between the in-phase and quadrature channels, causing a more noticeable degradation. Page Reducing The Modem Acquisition Range Ar To ensure the modem does not lock onto a true carrier image especially in systems operating at low symbol rates , slightly smaller frequency bins smaller than false lock distances are searched in an iterative manner.

The AO command is used for this, but only after at least one acquisition has been made. Adjusting the AO command causes the acquisition process to start at a frequency equal to the RS frequency plus the AO frequency. The coded BER curves include modem implementation losses, effects of asynchronous scrambling, and differential coding, but do not include the effects of adjacent carrier interference.

Page Figure Performance Qpsk Uncoded 1. Page Determining Doppler Buffer Size System clocking issues are the most common sources of periodic bit slip error , loss of modem synchronization, and problematic installations of satellite communications circuits. ComStream satellite modems support a synchronous data interface and, therefore, need stable and synchronous clocks and data to provide robust link performance.

Page Independently Timed Systems It is recommended that the master station have a plesiochronous, or elastic, buffer in its receive path, as in the first three clocking configurations shown in Figure This buffer allows newly received data to be clocked in with the clock recovered from the receive data. Page Installation Process Overview A shorter, less-detailed version of the CM installation procedure is available as a separate quick reference card that accompanies this guide. This quick reference is for those Page Step 1: Prepare For Cm Installation Outdoor dish antenna size Radio and frequency converter gains System monitor and control mechanism For a detailed review of these and other issues that will affect CM installation and configuration, as well as system performance, refer to the chapter on configuration examples.

This information can be used to verify shipments against orders without having to open the box. The customer name and P. Page Open The Carton Remote terminal - review the chapter on remote operations to familiarize yourself with the available remote commands and their syntax Both the front panel and a remote terminal - review both chapters on CM command operations Installation For additional information on using the correct power source and rules and regulations for attaching an international power cord refer to the Safety Precautions section.

To install and connect the CM, perform the following steps: 1. If remote operation is desired, connect the RS plug of an asynchronous data terminal to the remote control DB-9 connector. If an international AC power cable is selected, a locally compatible plug must be attached to the stripped and tinned bare wires of the cable in accordance with any local laws or regulations. Use the remote terminal or the front panel to configure the CM according to your system design and operating parameters.

Table lists commonly used configuration commands in front panel order. Acquire the Carrier Page Table Commonly Used Acquisition Commands Two items occur when carrier acquisition is complete: Rx Sync message on the front panel changes from white to green Unsolicited ST 0 message appears on the ASCII remote terminal screen If the modem does not acquire the carrier within its time period, an acquisition failure error code will be displayed.

Page Step 7: Validate The System 24 hours. The week duration is optimum as neighboring carriers on the satellite may interfere only at certain times during the week. The front panel will respond to all button presses except the Enter and Tx Enable buttons. This mode allows users to view, but not change, CM parameters, status information and other information displayed on the front panel LCD.

ASCII protocol is provided for use with character-based computer terminals. If the echo enable parameter EE is set to 1, the CM echoes the character back to the terminal for display on the screen. Page Issuing Remote Commands To query?

To display a list of command parameters, use the syntax DP. Page Command Summary Command Summary CM commands can be categorized into two memory types and four functional types. Memory types of configuration commands are listed in Table and command functions are listed in Table Page 84 [5]Autodial Fault Reporting AL2 is not currently supported [6]Command supported by ASCII protocol only; refer to the chapter on ComStream packet protocol for packet versions of these commands [7]Parameter range is 1 to ; default parameter is which includes all fault bits [8]Default is U.

Page Security Commands This command resets the password to the default and it also resets all modem parameters. Error Codes After a command has been issued, the CM may return an error message indicating the command request was not completed.

Page Table Remote Control Error Codes Firmware configuration or mode does not temporarily support the command CM internal Breakdown in microcontroller communications Reenter the command.

Repeated ER 5 communications error between cards The valuable front panel status and fault LEDs provide at-a-glance status checking enabling you to quickly scan the front panel to check for any abnormal operating conditions.

Page Lcd Display Configuration In general, these commands have parameters that can be modified and entered to change the operating characteristics of the CM Included in this category are the commands that direct the CM to perform real-time functions.

Monitor Provide query view-only information on the performance, operating environment, and nonfault-related conditions of the CM For information on the CF command, refer to the chapter on command descriptions. Yellow Illuminates as long as one or more of the CM test modes is active. Table lists the buttons used to navigate through the tree structure and to select and enter commands. These commands reflect the configuration of the CM and are organized in a tree structure that is accessed using the front panel buttons.

The command tree for a standard CM, is shown in Figure Page Table Cm Front Panel Command Tree Levels Commands that report performance and nonfault information provided by various monitoring points located within the CM Faults Commands that provide information on the status of the CM or indicate when an external piece of equipment is improperly configured or is faulty Page Command Display 5.

Select BConfig. Select Insert and press the Enter button. Select BMonitor and verify that a bit error was received. It is not necessary to scroll down the BMonitor command list. Page Entering Commands With The Terminal Emulator Entering Commands Commands not directly accessible from the command tree can be issued and with the Terminal modified from the front panel using the terminal emulator function.

Page Front Panel Command 4. Issue the command by pressing the Enter button. If the command was a query, the LCD will display the response for a few seconds and then redisplay :AA. These commands are summarized in the order in which they appear in the command tree, from top to bottom, and then left to right.

Included are Page Transmit Side Pattern Generator Transmit Side Pattern Generator The transmit side pattern generator generates a pseudorandom bit 2 pattern, or any 8-bit repeating pattern that you select. The pseudorandom pattern, used for most normal error analysis functions, is compatible with the 2 -1 patterns found on most error analysis test devices. Page Using The Bert 8. Disable the BERT when you are finished using it. These commands are listed first by type, BConfig and BMonitor, and then in the order in which they appear on the command lists.

The Bert is now enabled and the modem in IF loopback. Page Issuing Front Panel Commands Command Descriptions This chapter presents the procedures for issuing commands from both the remote terminal and the front panel, as well as a detailed description of all CM commands.

Security These commands control access to the remote port to prevent unauthorized operation of the CM over telephone lines or other types of remote access.

Command Descriptions During a power-up or soft reset RE of the CM, autoconfiguration default settings are reestablished. This command is used for advanced configurations only. For additional information, refer to the chapter on advanced usage. Page To disable autoconfiguration, issue the remote command ACP 0. Additional Information One benefit of the modular design of the CM is that multiple transmit or receive configurations are possible within one chassis.

To assist you in configuring the unit correctly, the CM automatically assigns cards to various logical transmit and receive paths as required. Page Use this command to enable or disable fault reporting and to allow or prevent unsolicited fault messages from being issued by the CM to a remote terminal. Packet protocol does not allow any unsolicited messages, regardless of the AL command parameter. The demodulator will acquire the carrier closest to the frequency at which the search begins.

For a CM operating at a symbol rate above ksps, acquisition time is typically less than one second. Reentering this command restarts acquisition. Page Acquisition Range Config NV Use this command to define the size of the frequency range over which the demodulator will search for the carrier. The acquisition range is expressed in hertz. Syntax Remote: BDI? After the completion of a self-test, the unit is returned to its original configuration.

The CM baud rate must match the baud rate of the remote control device. Use this command to stop, start, or reset the BERT. The BERT indicates synchronization based upon detection of fewer than n error bits out of m received bits, where n and m are defined in the BST command.

The default is 85, which converts to binary This mode is not available for configurations with multiple modulators.

It is however, available with multiple low-speed modem cards if the on-board RS interface is used. Page Use this command to monitor the channel error rate only if the demodulator is operating with decoding enabled. Page Table Cfg Card Types And Codes The response format is a single string that contains the slot number followed by a colon and an integer code for every CM card. Slots are delimited by commas. If a card is not present, the return code is 0.

Page Display Configuration Config V Use this command to view a summary of the current CM configuration as defined by the hardware cards and many NV memory-stored parameters. The DC command is not supported by ComStream packet protocol. For each card, one or more lines of configuration information is displayed.

The card description, slot location, software version, and any hardware-specific configuration attributes are included. Page Use this command to view a summary of current modem configuration and operating parameters. The DP command is not supported by ComStream packet protocol. For the packet protocol version of the DP command, refer to the chapter on ComStream packet protocol and the BD command.

Page Page Echo Enable Config NV Use this command to enable or disable the echoing of characters back to the remote unit when they are received by the modem. The command is for remote control ports operated with ASCII protocol only and has no effect on packet protocol operation. The response to this command is a decimal number that represents the contents of that bit fault log register. Page To designate a fault log overlay mask of , issue the remote command FLO Additional Information The CM has a bit fault log register with each bit assigned to represent a fault.

Page To set the fault conditions at , issue the FO command. Additional Information The CM has a bit current fault status register that has each bit assigned to represent a fault condition.

The FO command uses a bit mask register to designate which fault conditions will affect the status relay. Page 1 — inverted polarity; a fault condition is indicated by contact between the normally open contact pair of the Form-C status relay Fault conditions include only the user-specified fault conditions.

Any faults related to loss of power to the Cm cannot be indicated by the Form-C status relay. Page The bit mapping is binary , which is equivalent to decimal number 1. Therefore, the command to be issued is FRX 1. The CM will now report fault conditions only when the relays connected to pins 3 or 4 are closed or the relay connected to pin 5 is open.

If the modem ID is modified while the ID is displayed on the front panel, view the updated ID by navigating to any other command, and then return to the modem ID. Page CM The INF command performs a complete initialization and reset of all CM cards, returning all configuration parameters to their default settings and reconfiguring the NV memory map. Page Loopback connections are used primarily to isolate the location of a problem in a communications circuit. There are three basic loopback connections available.

There may be other loopback connections available depending upon the installed option cards. The CM always power-ups or resets with all loopbacks disabled. Command Descriptions Page Login Security V Use this command to log in to the remote control port security function and establish normal communications with the CM When LGE is set to 0, this command is not available and will return an error message.

This asynchronous character format for the CM remote control interface is independent of packet or ASCII remote control protocol selection. Page — seconds in one to six digits from 0 to Example To set the modem data time to 15 minutes and the time indicated on the CM real-time clock is a. Page ML 0. For more information on modulator latching clock, refer to the chapter on system configuration issues. The total number of characters used cannot exceed Page NV memory locations.

In the case of a power loss, power cycle, or soft reset, the CM configuration will return to the last settings stored in NV memory. It is strongly recommended that all cards in the unit have software version 4.

Page 4. The range of valid parameters may vary according to the specific configuration of the CM in terms of the option cards that are installed and their modes. Example To enter a data rate of 4. The range of valid parameters may vary according to the specific configuration of the CM in terms of the installed option cards and the modes in which they are configured. Page Use this command to set the data rate that is output by the demodulator after demodulating and decoding the receive signal.

This rate is the receive data rate, RT and RD signals, provided at the user data interface, unless the CM is configured with a framing unit, demultiplexer, or some other intermediate data processing card. The default is Example To set the receive data rate at bps, issue the remote command RD , or, from the front panel, enter as the parameter for RxDataRate.

This has the same affect as turning the power switch on the rear panel from Off to On. Upon reset, all conditions and parameters, with the exception of those stored in NV memory configuration parameters , are returned to default settings. Receive Offset Frequency Monitor Use this command to view the frequency offset between the demodulator synthesizer frequency setting remote RS command or front panel Rx Freq command and the actual demodulator RxIF carrier frequency.

The frequency of the RT clock is expressed in hertz. The range of valid parameters may vary according to the specific configuration of the CM in terms of the option cards that are installed and the modes in which they are configured.

The response to the ST command is a decimal number, indicating the conditions that are present at the time the query is made. Example To set a data rate of 4. Page Use this command to establish the data rate that is input to the modulator for transmission. In these cases, the TD parameter is the transmit data rate provided to the modulator by the intermediate data processing card.

The default is bps. Example To set the rate to 4. The real-time clock is used for various CM functions including time-stamped faults. For information on time-stamped fault reporting, refer to the VFT command. Additional Information For a CM system with a high-speed modulator card installed, refer to the MSM command in the option card manual for limitations to the TM command. Page Example To set the data rate to 9. The frequency of the TT clock is expressed in hertz.

View Faults Fault Use this command to view the CM stored fault history as a card-by-card list with detailed fault descriptions per card. The response consists of a card description and the slot location of that card, followed by descriptions of all existing fault conditions for that particular card. The modulator's TxIF output will be disabled One is based Network-Compatible on a standard CM configuration while the other example is based on a CM Operation that has two installed interface cards.

Page 7. Once the configuration parameters in steps 3 through 7 are set, they usually are not changed. Disable modulator and demodulator spectral inversion, enter MI 0 and DI 0. Page 5. Enable differential encoding and decoding, enter DM 2 and DD 2. Page 9. Select rate Viterbi encoding, enter TC 4.

Select rate Viterbi decoding, enter RC 4. Select a transmit data rate of bps, enter PTD Select rate Viterbi encoding, enter TC 3. Select rate Viterbi decoding, enter RC 3. Select a modem transmit data rate of 1,, bps, enter PTD This SMS-compatible system consists of The IF parameters frequency, level, etc.

The demodulator settings, receive clocking, doppler buffer. The maintenance page. The configuration parameters described below are set at this page. The modem's RS packet address. Valid addresses are If you have multiple devices connected to one RS bus, each device must have it's unique address. Common values are: The modem's fault log mask FLO , coded in the same way as "faultMask". Defines if the modems switches off the carrier on some faults conditions. The "DL" parameter.

See the Comstream manual for details. Remember to set the line parameters for the serial interface connected to the CM While the CM's factory preset setting is ,O,7,1 , the recommended line setting for the use with the sat-nms software is ,O,7,1.

The data rate field at the user interface contains no value. What happened? The primary data rate macros used to program the modem do not work in both directions.

If a data rate is set, the CM remembers this value and reports it to the software as the actual setting. This setting is cleared if any intermediate data rate value is changed e.