Options. Orolia NetClock/GPS 9283


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Options. Orolia  NetClock/GPS 9283  | Manualzz

Spectracom Corporation Model 9283

7 Options

Spectracom offers several options for the 9200 Series.

Option Description 9283

02

Front panel display & Second Serial

Port/Remote Port

03 Dial-Out Modem & ACTS Server

04 Rb (Rubidium) Oscillator *

05 OCXO Oscillator *

06 IRIG Input

08 SPS GPS Receiver

09 TCXO Oscillator *

*Choose one oscillator only.

STANDARD

OPTIONAL

OPTIONAL

OPTIONAL

OPTIONAL

STANDARD

STANDARD

Please contact Spectracom’s Sales department for information regarding any options you do not yet have that you may wish to purchase. Those options requiring additional explanation are detailed herein.

7.1 Option 03: Modem

7.1.1 Option 03 Basics

Option 03 provides the NetClock with the capability to use a modem to dial-out via an analog phone line for time retrieval if GPS reception is either lost or cannot be obtained due to site limitations. The modem can be configured in the software as either the primary external time reference or it can also be configured as a Secondary/Backup reference in case the primary reference is lost.

The modem interfaces to the NetClock via the Serial Setup Interface located on the rear of the

NetClock. This dual-function port provides the capability to initially configure the network settings and is also the interface for the modem.

If not initially purchased with the unit, Option 03 can be enabled (turned on) in the field. Please contact our Sales department to purchase this option. You will be sent a Hash key that can be entered in the NetClock to enable the security algorithms. The purchase of the option includes a Spectracom supplied compatible modem.

NOTE: The modem MUST be Hayes AT compatible and configured for this mode of operation to operate correctly with the unit. The Spectracom supplied modem is Hayes AT compatible.

NOTE: If the NetClock’s admin or user passwords are changed, the NetClock must be rebooted after this change to ensure proper modem operation.

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Model 9283 Spectracom Corporation

The cable needed to connect the modem to the NetClock is a DB9 male to DB9 male null modem serial cable. This should come with the modem package.

1. Connect one DB9 side of the null modem cable to the modem and the other DB9 side to the Serial Setup port located on the rear of the NetClock.

2. Connect the CAT2 telephone cable from the analog phone line to the modem.

3. Connect the modem power adapter to a power outlet.

The modem is configured from the System Modem Configuration screen, which includes the

Port Mode pull-down menu. The modem is connected to the Serial Setup port for normal operation. The pull-down menu allows the operator to select the mode in which the serial setup port will operate. Two options are available: Console mode and Client mode. The screen and the menu available at the left of the screen vary depending on the mode.

Console Mode: In this mode (Figure 7-1), Serial Setup port can be connected with a serial cable to a computer with a serial terminal program running. The serial setup software commands can then be used to interface with the unit. The modem operation will not be available while selected to this mode.

Client Mode: In this mode (Figure 7-2), the Serial Setup port can be connected to a modem for dialing out. The Serial Setup port will be unavailable for network configuration while in this mode.

NOTE: If the NetClock is switched repeatedly between Console and Client modes, the modem application may stop functioning. Reboot the NetClock to clear this condition.

ACTS Server Mode: This mode (Figure 7-3) configures the NetClock to answer telephone calls, using the modem, when connected to an analog telephone line. The modem connects to the NetClock in the same manner as for Client mode.

NOTE: Click “Submit” to apply the change to the modem mode. Return to Modem

Configuration to access the screen options for Client mode.

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Spectracom Corporation Model 9283

Figure 7-1: System Modem Configuration Screen, Console Mode

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Model 9283 Spectracom Corporation

Figure 7-2: System Modem Configuration Screen, Client Mode

After selecting Client mode, submitting the change, and returning to the Modem Configuration screen, the user may configure the modem through the Web UI:

Primary/Secondary Time Source: The modem can be configured as either the primary reference or a secondary/back-up reference. In the Secondary/Back-up mode of operation, all

GPS antenna problem alarms (indicating a short or open in the antenna cable) and SNMP traps associated with the GPS reference input will be fully enabled. By contrast, when Primary Time

Source is selected, the antenna problem alarm and associated SNMP traps for the antenna will not be generated. No indication of a problem with the GPS cable will be present or available.

The Client mode of operation does not affect the ability to receive GPS.

NOTE: If a unit initially operates without a GPS reference and primary mode of operation is selected, and a GPS antenna is later connected, the mode of operation should be changed to Secondary Time Source. This enables the GPS antenna problem alarms, which can be used in troubleshooting the system.

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Baud rate: Baud rates of 1200 and 9600 are available and can be selected from the pull-down menu.

Modem speaker: Toggles the modem speaker on or off during dial out.

Dialout now: (Only available in Client mode and only when the unit is not in time sync).

Checking this box and clicking submit will prompt the dial out modem software to attempt an immediate dial out procedure with the current settings if the unit is currently out of sync. When a unit is configured in client mode while it is in time sync, the “Dialout now” checkbox will be greyed-out (disabled).

The ACTS Server feature has been designed to operate similarly to the Automated Computer

Time Service (ACTS) provided by the National Institute of Standards and Technology (NIST). It is compatible with client programs that dial out to the NIST ACTS service for time synchronization, such as the NetClock when configured in Client mode. For best accuracy,

Spectracom recommends using a NetClock in Client mode in conjunction with a NetClock operating in ACTS Server mode.

Figure 7-3: ACTS Server Mode Selected

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Model 9283 Spectracom Corporation

Time Service Abbreviation: This field indicates the source from which a dial-out client is receiving Universal Coordinated Time (UTC). It is inserted in the ACTS timing message sent to the modem client. A time service abbreviation of SPEC will appear in the timing message as

UTC (SPEC).

DUT1 Value: This is a correction factor for converting UTC to an older form of Universal Time.

The value should always be a number between -.8 and .8 seconds. Adding DUT1 to UTC produces UT1 (a specific measure of time related to the rotation of Earth). The three-digit string entered in this field appears in the time messages sent to the modem client.

Leap Second: This field allows the user to specify the addition or removal of a leap second as well as the month and year in which this addition or removal will occur. The ACTS Server uses this information to notify the modem client of a pending leap second. It does so through time messages sent to the modem client.

Daylight Saving Time: This field is used to specify the month and day of the current year in which Daylight Saving Time (DST) is entered and exited. This information is included in the time messages sent to the modem client.

Modem Configuration File: The ACTS Server uses built-in, Hayes-compatible commands to configure the modem. Some modems may support additional or different commands, which may be required for proper configuration. If a modem configuration file is specified, the ACTS

Server will use the commands in that specified file to configure the modem, rather than using its built-in Hayes-compatible commands.

Modem Speaker: Clicking the appropriate radio button toggles the modem speaker on or off during dial out.

The ACTS Server Greeting (Figure 7-4), accessible using the left-hand menu, is a message sent to a modem client when a connection is made. The Acts Server Greeting screen allows the user to customize the greeting message for the specific application.

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Spectracom Corporation Model 9283

Figure 7-4: ACTS Server Greeting

The ACTS Server Statistics screen (Figure 7-5), accessible using the left-hand menu, provides all data for the current day and the previous day. For each day, it shows the number of attempted and completed calls during each hour of that day. This data is helpful in analyzing modem usage and balancing modem client call times.

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Model 9283 Spectracom Corporation

Figure 7-5: ACTS Server Statistics

The ACTS Server Log (Figure 7-6) helps the user monitor the behavior of the ACTS server daemon, including when it is started, when it is stopped, and how it is configured. The log records information about each time message it sends to the modem client. Data contained in the log is helpful in troubleshooting when there is a problem in communication between the

ACTS server and modem client.

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7.1.5 Modem Dial-Out Setup

Figure 7-6: ACTS Server Log

The modem dial-out feature is used as either a Secondary/Backup time reference when all other external time references become unavailable or can also be used as a primary reference if an external reference is not available for use (Such as the inability to receive GPS at a particular

NetClock/GPS Instruction Manual 7-9

Model 9283 Spectracom Corporation location). The System Modem Configuration screen (Figure 7-1) provides options to configure the operation of the dial-out modem feature from the left-hand menu. All fields will display the current system settings.

The Modem Dialout screen (Figure 7-7) is used to annotate the phone number used to obtain the time from and to determine how often the modem will be used to retrieve the current time.

Phone Numbers:

Prefix: The phone prefix is a number(s) that need to be dialed to reach an outside line.

Predefined: Stores two predefined number NIST-Colorado and NIST-Hawaii. These are the phone numbers to the National Institute of Standards and Technology modem time service.

Specified Number: This field will take any phone number that the user would like to use to dial out to obtain time.

Try Calling: This field specifies how many times the dial out modem software will try to connect to the selected phone number. Setting this field’s value to 0 will generate a warning because it will prevent any dial out to be made in any condition, effectively disabling the modem dial out feature.

Call Interval:

The call interval is used to manually configure how often the modem should dial-out for Time verification calls when the unit is in the holdover mode and time synchronization is normally derived from GPS (Secondary/Backup mode of operation) or time synchronization calls when the modem is selected as the primary mode of operation.

To prevent a leap second occurrence from being missed and a one second error being inserted into the NetClock, we recommend the Time Verification calls be placed less than once-permonth. Setting the Time Verification call period to longer than once-per-month can result in a one second error from the time a leap second is asserted by NIST until the next time verification/time synchronization call is placed.

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Spectracom Corporation Model 9283

Figure 7-7: System Modem Dial Out Screen (1 of 2)

To help prevent a loss of time synchronization condition from occurring, the call interval should be configured for a value of less than the holdover period. This will prevent the holdover period from expiring (which will cause loss of Time Sync) because the modem was configured to dialout after the holdover expired. For example, if the holdover period is set for two weeks, the call interval should be set to dial-out less than every two weeks. Otherwise, holdover will expire before the modem is scheduled for a dial-out and time synchronization will be lost.

Boot:

This field specifies how long the modem software will wait after being powered up to check the unit’s time synchronization status. If this time expires and the unit has not achieved time synchronization yet, the modem software will automatically dial out with the current settings at that time. Note that changes to this timer’s settings will not change the timeout of the current countdown if it has already begun (e.g. If the timer is set to 1 hour and then rebooted, the unit will countdown to 1 hour at power up. Changing the timer’s settings to 30 minutes will not affect the current countdown. The new 30 minutes value will only be used if another power cycle occurred). To skip the initial countdown, use the Dialout Now feature on the Modem

Configuration screen.

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Model 9283

.

Spectracom Corporation

Figure 7-8: System Modem Dial Out Screen (2 of 2)

If the modem is the primary mode of operation for time synchronization, the boot dial-out value should be set for a very short duration as the unit will not be able to achieve time synchronization without the modem placing a call. If the modem is strictly a backup to the external reference, this period can be lengthened to longer than the typical amount of time needed to synchronize to the external reference.

The System Modem Calibrate screen (Figure 7-9) is used to calibrate the modem for increased accuracy of the dial-out calls. The calibration procedure is not required but may be used to provide greater accuracy of future modem calls. The calibration process, using several dial-out helps compensate for inherit internal software processing lags as well as phone network delays as well. Different locations may experience different latencies as well as time of day latencies may also vary.

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Spectracom Corporation Model 9283

Figure 7-9: System Modem Calibrate Screen

The calibrate mode allows the user to define the typical latency for the geographic location as well as the time of day the modem is most likely to be used for time synchronization (such as for primary mode of operation).

Calibrate Status:

The status of calibration is displayed at the top of the screen. If the calibration has been made then the unit will say “calibrated”. If the latency has not been set or has been manually set, then the unit will say “not calibrated”. If the unit is currently calibrating then the number of successful calls will be displayed here.

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Model 9283 Spectracom Corporation

Calibrate Settings

Calibrate Now:

Calibrate now is based on the current settings. This will calculate the call latency and adjust all future calls based on this value. The call latency is based primarily on the phone system.

Therefore, this should be done when the unit is first set up and does not need to be done again unless it is connected to a different phone system.

Reset Latency Value:

This resets the latency value to the factory default. This can be done if the unit was accidentally set.

Latency Value/Manually Set Latency:

This box displays the current latency value. If the “manually set latency” box is checked then this can be edited to set the current latency.

Number of Calibration calls:

This is the number of calibration calls to be made before the modem is declared as calibrated.

The accuracy of the latency calculation depends directly on this number. The more calls that are made, the more accurate the calculation will be. This should not be lowered from the default, but it may be safely raised.

Calibration Call Interval:

This is the interval between calibration calls. This value, along with the number of calibration calls, will determine how long the calibration process will take.

The modem can be tested using the Web UI through the Modem Test screen (Figure 7-10).

Test Now:

Tests the modem to make sure it can correctly dial-out. This may only be done while in time synchronization from another source such as GPS. To test in other states, use the dial now button. The result of this test will be written to the log file.

Test On Interval:

Enables the modem test interval. If the unit has not made another type of call during this interval then a test call will be made.

Test Interval:

Sets the modem test interval. In order to set these values, the “Test On Interval” box must be checked. If the interval expires before another type of call is made then a modem test call will be made. To schedule a call when not in sync from another time source, use the “Call Interval” setting in the Dialout Settings page.

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Spectracom Corporation Model 9283

Figure 7-10: Modem Test Screen

There are four different types of modem dial-out calls that can be made. The call type is determined by the state of the system (after the call is finished) as well as user input.

Calibration calls happen upon a user request. Time verification calls happen on a user specified interval if holdover is entered from time synchronization with another source. Time synchronization calls occur when time synchronization is lost and on a user specified interval until another time source is available. Modem test calls happen when no calls have been made for a user specified time, or upon a user request. Because the modem determines how to use a

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Model 9283 Spectracom Corporation call after the call is finished it is possible to start a call as a certain call type and actually use it as another call type. Here is a description of each of the four possible call types.

Calibration calls are done to characterize the call latency. A user specified number of calls will be made over the calibration period and the average latency will be used to adjust all future calls. The calibration will only be done at the user’s request and may be started only while in sync from another time source. Calibration calls may be continued into holdover, but will be cut off if the unit goes out of sync at any point during the calibration period.

7.1.7.2 Time Verification Call

Time verification calls are made to verify the unit still has acceptable time and to correct for any leap seconds that may be asserted while the reference is not available. Calls will be made on a user specified time table. If the call interval is more than a month leap seconds may be missed.

If a leap second is to be inserted at the end of the month then the clock will be scheduled to do so. If the time is off by more than half a second then the unit will be immediately put into unsynchronized mode (time synchronization lamp will extinguish and time outputs will be ignored).

7.1.7.3 Time Sync Call

Time synchronization calls occur to set the second and sub second timers and to check for any leap seconds. If a call is successful the timer will be set and the unit will be put in holdover mode with the holdover timer reset. In addition if a leap second is to be inserted at the end of the month then the clock will be scheduled to do so. Time synchronization calls will be made once the unit has gone into unsynchronized mode until it obtains sync from another time source.

During this period, calls will be made on a user specified timetable or any time the unit goes out of sync.

7.1.7.4 Modem Test Call

Test calls are calls that make sure the modem is working. The modem will call out and check for valid time messages. The unit will log “test passed” if it was able to get good time messages or failed if it was not. No changes will be made to the system time. Testing can be done only in sync from another time source and can either be on a specified interval or as requested.

For the modem to function with the NetClock, the client mode must be selected in the System

Modem Configuration screen for the NetClock to accept the change from console mode.

If the unit is already powered-up and not synchronized, choosing dial-out now and hitting submit will cause the unit to connect to NIST. If the unit is already synchronized, this option is not available (The dialout now function is not available for operation if the NetClock is in either holdover or sync mode). To operate the modem if it is in currently in sync, disconnect the antenna and wait until the variable holdover period expires or power cycle the unit to clear the sync condition. Then, the dial-out now function will be available.

Once the NetClock has dialed and synchronized to NIST, the unit will be in holdover mode until the variable holdover period expires (Devices syncing to the NetClock will still sync) indicated by the sync light flashing green. After the variable holdover expires, the unit will declare loss of

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Spectracom Corporation Model 9283 sync (Sync lamp turns red) or when the scheduled Time Verification call occurs, the modem automatically dials NIST again. If connection is made, holdover is restored (Sync lamp flashes green again).

Verify proper operation of the modem by observing the status of the front panel sync lamp flashing green after connection to NIST and verifying the Model dial-out logs. The Modem

Dialout Log (Figure 7-11) is a running list of the NetClock’s modem activity. This log will have no activity if the NetClock is not equipped with a modem or if the modem has not yet been used.

Figure 7-11: Modem Dialout Log Screen

The Modem Dialout Log provides information concerning the numbers dialed, whether the dialouts were successful, and what changes have been applied to the subsecond counter and

NetClock/GPS Instruction Manual 7-17

Model 9283 Spectracom Corporation system clock. If calling a Spectracom ACTS server, additional information about each time message is logged, including the on-time character (what it is, when it is received) and the advance time included in the message.

If the sync lamp is also flashing red, this is because the GPS antenna is disconnected from the

NetClock. This is not directly related to the modem dial-out feature but if the antenna has been connected in the past, it is related to the reason why the modem is now dialing-out unexpectedly

(Antenna problem causing loss of GPS time Sync).

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Spectracom Corporation Model 9283

7.2 Option 04: Rubidium Oscillator

Option 04 provides the NetClock with a self-calibrating ovenized rubidium oscillator. The purpose of this oscillator is to provide a very accurate time base when GPS is either lost or cannot be obtained due to site limitations. It is also used to provide a very stabile and accurate

10 MHz output with a high degree of holdover if GPS is lost. Because of its high degree of stability, this oscillator provides the ability to greatly extend the hold-over period when GPS is not present. Extending the hold-over period allows the unit to provide very accurate and useable time stamps and a 10 MHz output for a longer period of time once time synchronization has been lost.

NOTE: The NetClock must be ordered with Option 04 installed at the time of the initial purchase. This option cannot be added after the NetClock has been shipped from the factory.

The Rubidium oscillator is atomic in nature but requires no MSDS.

7.2.1 Comparison of the Rubidium oscillator to the OCXO and standard TCXO oscillators:

10 MHZ frequency output:

Rubidium oscillator (Option 04): 1x10 -12

typical 24-hour average locked to GPS,

1x10

-11

per month typical aging unlocked.

OCXO oscillator (Option 05): 1x10

2x10

-11

-9

typical 24-hour average locked to GPS,

per week typical aging unlocked.

TCXO oscillator (Standard): 1x10

-10

typical 24-hour average locked to GPS

Time drift while the NetClock is in Holdover mode (Loss of primary/backup reference):

Oscillator Option

Rb Option 04

Estimated Error Rates

0.18 microseconds / hour (nominal)

Time to reach 2 ms

463 days

OCXO

TCXO

TCXO

Option 05

Standard

Standard

72 microseconds / hour (nominal)

1.0 milliseconds / hour (nominal)

7.2 milliseconds / hour (worst case)

28 hours

2 hours (typical)

17 minutes*

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Model 9283 Spectracom Corporation

7.3 Option 05: OCXO Oscillator

Option 05 provides the NetClock with a self-calibrating ovenized quartz oscillator. The purpose of this oscillator is to provide a very accurate time base when GPS is either lost or cannot be obtained due to site limitations and a very precise 10 MHz output. Because of its high degree of stability, this oscillator provides the ability to greatly extend the hold-over period when GPS is not present. Extending the hold-over period allows the unit to provide very accurate and useable time stamps and a 10 MHz output for a longer period of time once time synchronization has been lost.

The OCXO characteristics are not quite the same as the Option 04 Rubidium oscillator, but are still much greater than the standard TCXO that is used in the product when option 4 and 5 are not installed.

NOTE: The NetClock must be ordered with Option 05 installed at the time of the initial purchase. This option cannot be added after the NetClock has been shipped from the factory

7.3.1 Comparison of the OCXO to the Rubidium and Standard TCXO oscillators:

10 MHZ frequency output:

OCXO oscillator (Option 05): 1x10

2x10

-11

-9

typical 24-hour average locked to GPS,

per week typical aging unlocked.

Rubidium oscillator (Option 04): 1x10

1x10

-12

-11

typical 24-hour average locked to GPS,

per month typical aging unlocked.

TCXO oscillator (Standard): 1x10

-10

typical 24-hour average locked to GPS.

Time Drift while the NetClock is in Holdover mode (Loss of primary/backup reference):

Oscillator Option

OCXO

Estimated Error Rates Time to reach 2 ms

Option 05 72 microseconds / hour (nominal) 28 hours

Rubidium Option 04 0.18 microseconds / hour (nominal) 463 days

TCXO Standard 1.0 milliseconds / hour (nominal) 2 hours (typical)

TCXO Standard 7.2 milliseconds / hour (worst case) 17 minutes*

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Spectracom Corporation

7.4 Option 06: IRIG Input & 1PPS Input

Spectracom NetClock units equipped with Option 06 support IRIG and 1PPS inputs.

Model 9283

Signal:

AM Carrier:

AM Signal Level:

DCLS Signal Level:

IRIG B, amplitude modulated sine wave (AM) or pulse-width-coded (DCLS, Differential).

IRIG B 1000 Hz.

500mV to 10V p-p (Modulated 2:1 to 6:1).

>10k ohms. RS-485 or TTL with DCLS IRIG IN connected to ground.

BNC Connector Pin-out

Center Pin IRIG HI

DB9 Connector Pin-out

Pin 1

Pin 2

Pin 3

Pin 4

Pin 5

Pin 6

Pin 7

Pin 8

Pin 9

NC

Ground

Ground

DCLS IRIG IN + (for single ended)

DCLS IRIG IN -

NC

NC

NC

NC

Signal Level: TTL compatible (High trigger is 2.1 V, low is 0.9 V),

High Z (> 10k ohms), Active rising edge.

From the IRIG Input setup screen (Figure 7-12), the user may configure the source year to be used with the IRIG input time code. By default, the year fields in the IRIG message are ignored and a user-defined value is used.

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Model 9283 Spectracom Corporation

NOTE: Make sure the year is set correctly when the NetClock is installed. If the year is not set correctly before NTP achieves time synchronization, it will use the value entered. The unit will also default to the year entered if it is powered down during the rollover of the year. If the NetClock was not switched on during the rollover, this value must be updated.

NOTE: When the IRIG Input year is updated, the NTP server must be restarted from the NTP

Web UI page (or the NetClock rebooted) for the new year value to take effect.

Figure 7-12: IRIG Input Screen

The IRIG/ACTS Server Capable NetClock supports an externally provided 1PPS signal, which is supplied as a reference for improved accuracy during holdover. The NetClock auto-detects this signal on the 1PPS Input connector (when provided) and uses it to maintain time only when the primary time reference (such as IRIG input) has become unstable or is no longer available.

The 1PPS signal is also used between modem dial-out adjustments.

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Spectracom Corporation Model 9283

When a stable 1PPS signal is connected to the NetClock, it is recommended that the holdover timeout on the holdover setup page is adjusted to a value suitable to the desired accuracy for

1PPS source.

Oscillator Recommended Holdover Timeout

TCXO (~2 ppm)

OCXO (~.02 ppm)

2 hours

24 hours

NOTE: Any externally provided 1pps signal should have a MINIMUM accuracy of 10ppm.

When the NetClock receives an externally-provided 1PPS input, this is indicated on the System

Status page in Time Source field (Figure 7-13). Such an indication (“Ext 1PPS”) means that the

NetClock has received time information from the specified time source, but is currently maintaining time using the 1PPS input signal.

Figure 7-13: System Status Screen (1PPS Input Indicated)

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Model 9283 Spectracom Corporation

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