Arbiter Systems 120A User manual

MODEL 120A
GNSS SYNCHRONIZED CLOCK
USER MANUAL
ARBITER SYSTEMS, INC. PASO ROBLES, CA 93446
U.S.A.
WWW.ARBITER.COM

Model 120A
GNSS Synchronized Clock
Operation Manual
Chapter 1
General
Chapter 2
Specifications
Chapter 3
Physical Configuration
Chapter 4
Operation
Chapter 5
Instrument Configuration
Chapter 6
Firmware Updates
Appendix A
IRIG-B Time code
Appendix B
Serial Communications and Command Set
Appendix C
GPS Antenna Placement
Copyright Arbiter Systems Incorporated August 2021 All rights reserved. International copyright secured.
Publication number: PD0058200A
Reorder number: AS011700

Description This manual is issued for reference only, at the convenience of Arbiter Systems. Reasonable effort
was made to verify that all contents were accurate as of the time of publication. Check with Arbiter Systems at the
address below for any revisions made since the original date of publication.
Contact Information:
Arbiter Systems, Inc.
1324 Vendels Circle, Suite 121
Paso Robles, CA 93446
[phone]
www.arbiter.com
[email protected]om
[email protected]m
What This Manual Covers
This manual describes the set up and operation of the Model 120A series GNSS synchronized clocks.

LIMITED WARRANTY Arbiter Systems makes no warranty, expressed or implied, on any product manufactured or
sold by Arbiter Systems except for the following limited warranty against defects in materials and workmanship
on products manufactured by Arbiter Systems.
Products manufactured by Arbiter Systems are guaranteed against defective materials and workmanship under
normal use and service from the date of delivery for a period five years. The responsibility of Arbiter Systems
under this warranty is limited to repair or replacement, at Arbiter Systems’ option, of any product found to be
defective. Arbiter Systems shall have no liability under this warranty unless it receives written notice of any
claimed defect.
For warranty service or repair, products must be returned to a service facility designated by Arbiter Systems.
Buyer shall prepay all shipping charges to Arbiter Systems, and Arbiter Systems shall pay shipping charges
incurred in returning the product to Buyer. However, Buyer shall pay all shipping charges, duties and taxes for
products returned to Buyer in a country other than the United States of America.
THE WARRANTY SET FORTH HEREIN CONSTITUTES THE ONLY WARRANTY OBLIGATIONS OF ARBITER SYSTEMS,
EXPRESSED OR IMPLIED, STATUTORY, BY OPERATION OF LAW, OR OTHERWISE. ARBITER SYSTEMS DISCLAIMS ANY
WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, AND BUYER EXPRESSLY WAIVES ALL
OTHER WARRANTIES.
This limited warranty does not extend to any product, which has been subject to:
1. Improper use or application, abuse, or operation beyond its rated capacity, or contrary to the instructions
in the operation and maintenance manuals (if any);
2. Accident;
3. Repair or maintenance performed by Buyer, except in accordance with the operation and maintenance
manuals, if any, and any special instructions of Arbiter Systems;
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instrument is not covered by this warranty, an estimate will be made before the repair work begins, if
requested.

Table of Contents
1 General ............................................................................................................................................................... 10
1.1 Overview..................................................................................................................................................... 10
1.2 Equipment Included ................................................................................................................................... 10
1.2.1 Model 120A GNSS Synchronized Clock............................................................................................... 10
1.2.2 Antenna Assembly (AP015700) .......................................................................................................... 10
1.2.3 Antenna Cable Assembly (CA0034700).............................................................................................. 10
1.2.4 Mounting Flanges (HD0089800)......................................................................................................... 10
1.2.5 Input / Output Connectors (CN0019202)........................................................................................... 10
1.2.6 Input / Output Connectors (CN0019204)........................................................................................... 10
1.2.7 Setup Guide (PD0058300) .................................................................................................................. 10
1.3 Equipment Available................................................................................................................................... 11
1.3.1 Micro USB Cable (CA0033700) ........................................................................................................... 11
1.3.2 BNC (Male) Breakout to 100 mm Wires (AP0003400) ....................................................................... 11
1.3.3 BNC (Female) Breakout to 100 mm Wires (AP0008900).................................................................... 11
1.3.4 BNC (Female) Breakout to Screw Terminals (AP0014900)................................................................. 11
1.3.5 BNC (Male) Breakout to Screw Terminals (AP0015000) .................................................................... 11
2 Specifications...................................................................................................................................................... 12
2.1 Receiver Characteristics ............................................................................................................................. 12
2.1.1 Input Signal......................................................................................................................................... 12
2.1.2 Time Accuracy..................................................................................................................................... 12
2.1.3 Satellite Tracking ................................................................................................................................ 12
2.1.4 Acquisition.......................................................................................................................................... 12
2.1.5 Antenna .............................................................................................................................................. 12
2.1.6 Antenna Cable .................................................................................................................................... 12
2.2 Interface ..................................................................................................................................................... 12
2.2.1 Antenna Input..................................................................................................................................... 12
2.2.2 LED Annunciators ............................................................................................................................... 12
2.2.3 Communication Ports......................................................................................................................... 13
2.2.4 Outputs............................................................................................................................................... 13
2.2.5 Relay ................................................................................................................................................... 13
2.2.6 Reset Function.................................................................................................................................... 13
2.3 General ....................................................................................................................................................... 14
2.3.1 Power Requirements.......................................................................................................................... 14
2.3.2 Dimensions ......................................................................................................................................... 14
2.3.3 Weight ................................................................................................................................................ 14
2.3.4 Temperature....................................................................................................................................... 14

3 Installation...........................................................................................................................................................15
3.1 Instrument...................................................................................................................................................15
3.1.1 Location...............................................................................................................................................15
3.1.1 Instrument Mounting..........................................................................................................................15
3.1.2 Power Requirements...........................................................................................................................15
3.2 Antenna.......................................................................................................................................................16
3.2.1 Antenna Input .....................................................................................................................................16
3.2.2 Antenna Location................................................................................................................................16
3.2.3 Antenna Mounting..............................................................................................................................16
4 Configuration ......................................................................................................................................................17
4.1.1 Connecting ..........................................................................................................................................17
4.1.2 Permissions .........................................................................................................................................17
4.1.3 Sending Commands.............................................................................................................................18
4.2 Clock Configurable Parameters...................................................................................................................18
4.2.1 GNSS....................................................................................................................................................18
4.2.2 Local Offset..........................................................................................................................................18
4.2.3 DST ......................................................................................................................................................18
4.2.4 Outputs................................................................................................................................................18
4.2.5 SPST Relay Contact..............................................................................................................................19
4.2.6 Serial Port............................................................................................................................................20
4.2.7 Downloading a Configuration File.......................................................................................................20
4.2.8 Uploading a Configuration File............................................................................................................20
5 Operation ............................................................................................................................................................21
5.1 Startup.........................................................................................................................................................21
5.2 Reset............................................................................................................................................................21
5.3 Faults...........................................................................................................................................................22
6 Firmware Updates...............................................................................................................................................23
6.1 Requirements..............................................................................................................................................23
6.2 Procedure....................................................................................................................................................23
6.3 Verifying ......................................................................................................................................................23
7 Appendix .............................................................................................................................................................24
7.1 IRIG-B Timecode..........................................................................................................................................24
7.1.1 IRIG-B IEEE C37.118.1..........................................................................................................................24
7.2 Serial Commands.........................................................................................................................................25
7.3 Constructing a Custom String......................................................................................................................31
7.3.1 Custom Broadcast String Setup Example............................................................................................33
7.4 Troubleshooting..........................................................................................................................................34

7.5 Glossary ...................................................................................................................................................... 34
7.6 Drawings..................................................................................................................................................... 35

1General
1.1 Overview
The Model 120A GNSS Synchronized Clock is a multi-satellite system (GPS, Galileo, GLONASS, BeiDou) timing
source. Designed as an economical solution for reclosers and other enclosed installations, includes a rugged, low-
profile, bulkhead-mount antenna with 5 meters of cable.
The Model 120A has a seventy-two channel receiver, capable of tracking up to 3 satellite constellation systems
simultaneously providing a 100 ns rms accuracy. Two pluggable terminal strip outputs provide IRIG-B
unmodulated, 1 PPS, or Programmable Pulse; software selectable. These outputs are configurable to a 50 ohm
driver or a high capacity driver. The Model 120A comes standard with two communication ports, one RS-232 and
one USB. A SPST relay is also included and is configurable to Out of Lock, Fault, Alarm, Stabilized, or
Programmable Pulse. Low-voltage dc power input accepts + 8 Vdc to + 32 Vdc.
1.2 Equipment Included
1.2.1 Model 120A GNSS Synchronized Clock
Instrument comes with 1 four-position and 4 two-position pluggable terminal strip connectors installed and flange
mounts attached.
1.2.2 Antenna Assembly (AP015700)
An active low-profile, weatherproof GPS patch antenna is included. Designed for bulkhead mounting, the antenna
requires 2.5 to 5.5 Vdc on the TNC connector for power.
1.2.3 Antenna Cable Assembly (CA0034700)
A 5 meter (16 foot) RG-174/U cable is provided to connect the Model 120A to the antenna. The cable is
terminated with a female TNC connector on one end and female F connector on the other end and has a
characteristic impedance of 50 ohms.
1.2.4 Mounting Flanges (HD0089800)
The included mounting flanges (2) are pre-attached.
1.2.5 Input / Output Connectors (CN0019202)
Four 2 position pluggable terminal strip connectors for connecting the power, relay contacts and signal outputs
are pre-attached to the Model 120A.
1.2.6 Input / Output Connectors (CN0019204)
One 4 position pluggable terminal strip connector for connecting serial communication port is pre-attached to the
Model 120A.
1.2.7 Setup Guide (PD0058300)
Brief instructions to get started using the Model 120A.

1.3 Equipment Available
1.3.1 Micro USB Cable (CA0033700)
A 6 ft USB 2.0 A male to micro 5 pin male 28/24 AWG Cable w/ Ferrite Core (Gold Plated).
1.3.2 BNC (Male) Breakout to 100 mm Wires (AP0003400)
Transitions two wires to a male BNC connection.
1.3.3 BNC (Female) Breakout to 100 mm Wires (AP0008900)
Transitions two wires to a female BNC connection.
1.3.4 BNC (Female) Breakout to Screw Terminals (AP0014900)
Transitions wires to a female BNC connection via screw terminals.
1.3.5 BNC (Male) Breakout to Screw Terminals (AP0015000)
Transitions wires to a male BNC connection via screw terminals.

2Specifications
2.1 Receiver Characteristics
2.1.1 Input Signal
Accepts GPS L1 C/A, Galileo E1B/C, GLONASS L1OF and BeiDou B1I on F-type connector.
2.1.2 Time Accuracy
± 100 ns rms when receiving 4 or more satellites.
2.1.3 Satellite Tracking
Seventy-two channel receiver simultaneously tracks 2 frequencies with the ability to synchronize to 72 satellites
(defaults: GPS/Galileo and GLONASS). GLONASS and BeiDou cannot be selected at the same time.
2.1.4 Acquisition
Receiver: 30 seconds
Output stabilization: 2 minutes
2.1.5 Antenna
Included, bulkhead mount, active (+5 VLNA power) GPS L1 frequency, TNC connector.
2.1.6 Antenna Cable
RG-174/U, 5 m (16 feet) included. Terminated with TNC and F-Type connectors.
2.2 Interface
The Model 120A interface consists of a F-Type antenna connector, 4 LED annunciators, and a twelve-position
pluggable 5 mm terminal strip on one panel with a micro USB connector, data LED and a recessed reset button on
the opposite panel.
Figure 2-1: Model 120A End Panels
2.2.1 Antenna Input
The antenna input is a F-type connector for active GPS/GNSS antennas and provides 5 V LNA power (100 mA
max.).
2.2.2 LED Annunciators
Locked (green): Illuminated when the clock is actively tracking and synchronizing to satellite signals.
Unlocked (red): Illuminated when the clock is not receiving satellite signals.
PWR (green): Illuminated when the clock is receiving sufficient DC power to operate the unit.
Fault (red): Illuminated when the clock detects a fault.

2.2.3 Communication Ports
USB 2.0 micro USB connector emulates serial com port with a 115200 baud rate, 1 stop bit, 8 data bits and no
parity. Used for configuration and firmware updates.
RS-232 Port communications port on 3 pins of the pluggable terminal strip (Txd, Rxd, Gnd). Used for configuration
and serial broadcast signals.
•200 to 115200 baud rates
•7 or 8 data bits
•1 or 2 stop bits
•Even, Odd or None parity Used for configuration and serial broadcast signals.
2.2.4 Outputs
There are two logic level (+5 Vdc) programmable pulse outputs that can be configured to one of the signals listed
below with the choice between UTC or Local time and low (50 ohm) or high drive capability.
•IRIG-B
•IRIG-B with C37.118 (2011) extensions
•DCF77
•Pulse Per Day (PPD)
•Pulse Per Hour (PPH)
•Pulse Per Second (PPS)
2.2.5 Relay
Form A (SPST-N)), 400 V peak ac/dc. 20-40 ohms on resistance.
Signal: Out of Lock, Fault, PPM, PPH, PPD, ST
Fail Safe: In Unlocked/Fault state (power off), contacts are open.
2.2.6 Reset Function
There is a recessed reset button on right of panel with USB port and LED. The reset button has two functions:
1. Restart the Model 120A: Press the button momentarily to restart.
2. Reset the factory defaults: Press and hold the reset button in until the 4 LEDs next to the output
connector start blinking to reset.
Factory defaults:
Login
User: admin
Password: password
Timeout: 60 minutes
GNSS
Satellites: GPS GLONASS Galileo
Antenna Delay: 30 nS
Out1 (Programmable Pulse)
Signal: IRIG-B unmodulated
C37.118: On
Time reference: UTC
Drive level: Low (50 ohms)
Out2
Signal: IRIG-B unmodulated
C37.118: On
Time reference: UTC
Drive level: Low (50 ohms)
Relay
Signal: Out of lock

Communication Ports
Baud Rate: 115200
Data Bits: 8
Parity: None
Stop Bits: 1
Broadcast: Off
Time
Local offset: 0 hours
Daylight Savings Time: Off
2.3 General
2.3.1 Power Requirements
Input accepts +8 to +32 Vdc and is not isolated, negative terminal is connected to chassis ground.
2.3.2 Dimensions
Chassis: 110 x 85 x 30 mm (4.3 x 3.4 x 1.2 inch)
Chassis with mounting brackets: 140 x 85 x 30 mm (5.5 x 3.4 x 1.2 inch)
2.3.3 Weight
0.45 kg (1 lb)
2.3.4 Temperature
-40˚ C to 85˚ C

3Installation
3.1 Instrument
All output connections (including the RS-232 port) use Phoenix type pluggable terminal connectors with 5 mm
spacing. The connector accepts between 0.25 mm and 2.5 mm diameter wire. To connect wires to any of the
terminals, strip the insulation back to expose about 6.35 mm (0.25 in) of bare wire (DO NOT tin the bare end with
solder), insert the stripped wire into the terminal and turn the screw down (clockwise) to secure it in the
connector.
3.1.1 Location
The Model 120A GNSS Synchronized Clock was designed for enclosed applications and will operate over a -40˚ C
to 85˚ C temperature range. The small size allows for the unit to fit in small spaces. The case is not waterproof so
it must be kept in a weather protected location.
3.1.1 Instrument Mounting
The Model 120A comes with two removable flanges with slots that can be used to secure the unit to a panel or
shelf.
3.1.2 Power Requirements
The Model 120A accepts a dc input voltage between +8 and +32 Vdc. The maximum power required for operation
is 5 Watts. The power is connected using a two terminal Phoenix type pluggable terminal connector with 5 mm
spacing. The negative terminal of the power inlet is connected to chassis ground so the power source must be
positive grounded. The power inlet is protected by an internal auto-recovering thermal fuse.

3.2 Antenna
3.2.1 Antenna Input
The Model 120A antenna input is a female Type F connector that accepts GNSS signal inputs. The 120A is designed
to work with active antennas and supplies 5 Vdc to energize the antenna.
3.2.2 Antenna Location
The GPS antenna supplied with the 120A is waterproof and designed for outdoor use in all weather conditions and
is designed to mount on the top of the control box through a 23 mm (7/8 inch). The antenna can be mounted in
an alternate location and comes standard with a five-meter (16 feet) antenna cable.
3.2.3 Antenna Mounting
Position the antenna to have a clear view of the sky in all directions of the compass for best satellite tracking.
1. Place the gasket onto the antenna.
2. Pass the antenna base through the 23 mm
(7/8 inch) hole in the top of the cabinet.
3. Spin the plastic base nut onto the antenna.
4. Spin the metal locking nut onto the antenna.
5. Attach the TNC cable end to the antenna and
and tighten.
6. Route the cable as needed to the clock.
7. Attach the F-type connector to the clock and
hand tighten.

4Configuration
All clock configuration is performed via the USB port or the RS-232 port using a standard ASCII terminal program
and serial commands, there are no physical jumpers or switches to set. Firmware updates are only available over
the USB management port.
4.1.1 Connecting
The CONFIG PORT and the RS-232 port have equal functionality except firmware updates must use the CONFIG
PORT. To start the configuration process, make a serial connection using a terminal program with the following
default settings:
•Baud Rate: 115200
•Data Bits: 8
•Stop Bits: 1
•Parity: N
Default Username: Administrator
Default Password: P4ssw_rd
When first connecting, press ENTER to see the Username prompt, type the username, press ENTER, and then type
the password and press ENTER. A successful login will display the prompt “>”. An unsuccessful login will display
the message: “Error 9: Invalid username/password”. If you receive this message double check the password,
username, and make sure that CAPS LOCK is not on.
4.1.2 Permissions
The available command set depends upon the user role. The default user “Administrator” (role: Admin Config)
allows total access to the command set without any restrictions. There are four roles available for each user:
1. Admin Config –Ultimate user role with no restrictions; has all available commands: add, audit, broadcast,
delete, dst, firmware, gnss, localoffset, logout, ool, output, password, position, readconfig, relay, serial,
status, time, timeout, users, whoami, writeconfig, and ?.
2. Admin –Administration role limited to configuring user-related settings with the following commands:
add, audit, delete, firmware, logout, password, readconfig, status, timeout, users, whoami, writeconfig,
and ?. Other commands are limited to status only.
3. Config –Configuration role limited to configuring unit-related settings with the following commands:
broadcast, dst, firmware, gnss, localoffset, logout, ool, output, password, position, relay, serial, status,
time, timeout, whoami, and ?.
4. Read Only –Operator role limited to status only with the following commands: broadcast, dst, firmware,
gnss, localoffset, logout, ool, output, password, position, relay, serial, status, time, timeout, whoami, and
?.
Attempting to enter commands without the proper “role” will display the message: “Error 7: No Permission”.
User Notes:
1. Multiple users and roles can be added.
2. Username length is a minimum of 8 alphanumeric characters and must start with an alpha character.
3. Password length is a minimum of 8 characters and must contain 1 upper case, 1 lower case, 1 number,
and 1 non-alphanumeric character.
4. Command syntax for setting usernames and passwords requires the use of quotes around the values.

4.1.3 Sending Commands
The serial commands are divided by security role: Admin, Config and Read Only. All users have access to the read-
only command set in addition to their primary role. All commands use the following nomenclature:
Text without brackets is the command
Text within <variable> are variables required for the command to function
Text within {optional} are optional parameters
Text within “<text>” quotes indicate the required parameter needs to have quotation marks around it.
For example, to add a user named operator1 with an admin role and a password of Admin-120A without the
ability to change the user password would have two acceptable commands.
The syntax is:
add “<username>” “<password>” <role> {<pw_perm>}
and filled in, would look like:
add “operator1” “Admin-120A” 2 0
or
add “operator1” “Admin-120A” 2
The {<pw_perm>} portion of the command is optional and if it is not specified will be 0.
A helpful tip is the use of the “?” command. A lone question mark will display the available commands for the
logged in user. A “?” following a command will give the available options and syntax for that command.
Example: “dst ?” will return the syntax for setting Daylight Saving Time.
4.2 Clock Configurable Parameters
4.2.1 GNSS
Global Navigation Satellite Systems setting allows to pick the satellite constellation to track and get timing
information from. The Model 120A can receive GPS, Galileo, GLONASS and Beidou signals and can actively track
up to 3 systems at a time. The Model 120A cannot receive both GLONASS and BeiDou simultaneously.
4.2.2 Local Offset
Local Offset allows the user to set a local time zone and is entered in times +/- from UTC time. For example,
Pacific Standard Time is entered as -8 as it is 8 hours behind UTC.
4.2.3 DST
Daylight Savings Time is the seasonal adjustment to adjust local time by adding an hour according to your local
laws. The Model 120A can be set to off (no time added), on (1 hour added to your local time) and auto (add an
hour automatically according to the custom programming). The auto selection allows the user to set the month,
day, hour, and minutes when an hour is added and then removed.
4.2.4 Outputs
There are two output signals on the Model 120A, Out1 and Out2. The outputs are limited to digital signals and are
selectable between 2 different drive levels. The low drive (LD) level (50-ohm impedance) is designed to drive
lighter loads and minimizes overshoot and ringing. The high drive (HD) level is designed to drive multiple heavy
loads and is current limited to 250 mA of drive current with a 10-ohm source resistance. Each output is
independently configured to one of the following programmable pulse signals in either UTC time or Local time:
•Unmodulated IRIG-B
•Unmodulated IRIG-B with C37.118
•DCF77

•Pulse Per Day (PPD)
•Pulse Per Hour (PPH)
•Pulse Per Second (PPS)
4.2.4.1 Unmodulated IRIG-B
IRIG-B is a serial time code developed by the US military’s Inter-Range Instrumentation Group for range timing
that has been adopted by many different industries. The IRIG-B timecode has a time frame of 1 second with an
index count of 10 milliseconds and contains Time Of Year (TOY) in days, hours, minutes, seconds, and year
information in a BCD format and seconds-of-day in SBS. The Model 120A supports the unmodulated (DC level
shift) versions of the IRIG-B standard B000 and B003, B004 (RCC 200-16) in both local or UTC time. The control
functions of B000 and B004 follow IEEE C37.118 timing specifications.
4.2.4.2 DCF77
DCF77 is a one-minute time code with an amplitude-modulated, pulse-width coded 1 bit/s data signal. The first 20
bits are special flags. The minutes are encoded in bits 21–28, hours use bits 29–34, and the date is transmitted
during seconds 36–58. In the event of an added leap second, a 0-bit is inserted during the 59th bit.
4.2.4.3 Pulse Per Day (PPD)
Provides a pulse every day at the start of the day with a 10 ms pulse width.
4.2.4.4 Pulse Per Hour (PPH)
Provides a pulse once an hour at the top of the hour. The delay value, from 0 to 10000 ms can be used to offset
from top of the hour.
4.2.4.5 Pulse Per Second (PPS)
The one pulse-per-second output is a pulse transmitted at the start of every second with a 10 ms pulse width. The
rising edge is the on-time mark of the signal.
4.2.5 SPST Relay Contact
A Form A SPST solid state relay provides contact closure for several clock conditions and programmable pulse
modes. The contacts are normally open (NO). “Normally” refers to the relay condition when the clock is powered
off. Out of Lock and Fault are considered failsafe as when the condition is met the relay is asserted and the
contacts are closed. Power failure will result in open contacts and indicates a fault and out of lock condition.
Available settings are:
•Disabled
•Open
•Closed
•Out of Lock (OOL)
•Fault
•Pulse Per Minute (PPM)
•Pulse Per Hour (PPH)
•Pulse Per Day (PPD)
•Single Trigger (ST)
OOL –Indicates if the GNSS receiver is receiving enough satellites to produce an accurate time. The contacts will
be open when there are not enough satellites and will be closed when satellites are being tracked. The
activation/deactivation can be delayed from 1-99 minutes.
Fault –Indicates if an internal error is affecting proper operation of the Model 120A. The relay contacts will be
open in the presence of a fault and closed under normal operation. Please see section 5.3 for detailed fault
information.
PPM –Provides a 10 ms contact closure once a minute at the top of the minute.
PPH –Provides a 10 ms contact closure once an hour at the top of the hour.
PPD –Provides a 10 ms contact closure once a day at the start of the day.

ST - Provides a pulse transition at the chosen day, month year, hour, minute, and second. Single Trigger polarity
may start as either high (positive) or low (negative). When the trigger occurs, it transitions to the opposite polarity
and remains at that value until Single Trigger is deliberately reset.
4.2.6 Serial Port
The Model 120A comes with a 3-wire RS-232 DTE serial interface that can be used to configure and communicate
with the clock or to output a broadcast string. The serial port baud, data bit length, stop bits and parity are
configurable. The broadcast mode can be set to 1 of 9 predefined outputs or the custom setting which allows the
user to configure one. A null-modem cable is required for proper communications.
120A Terminal
Tx Receive
Rx Transmit
GND Ground
4.2.7 Downloading a Configuration File
The Model 120A current configuration can be downloaded to a binary file using the serial command “readconfig”.
Sending the “readconfig” command will initiate an X-modem transfer and the Model 120A will wait for an X-
modem handshake to start sending the file when ready. The user must use a terminal program capable of an X-
modem transfer to receive the file. A successful process will look like:
>read
Start binary file transfer (Xmodem receive)...
>
Success!
>
4.2.8 Uploading a Configuration File
The Model 120A configuration can be uploaded to a binary file using the serial command “writeconfig”. Sending
the “upconfig” command will initiate an X-modem transfer and the Model 120A will wait for an X-modem
handshake to start sending the file when ready. The user must use a terminal program capable of an X-modem
transfer to receive the file and when done must log into the Model 120A again. A successful process will look like:
>write
Start binary file transfer (Xmodem send)...
>
Config updated, rebooting unit...
>ð
120A Main: 1.01-16
Boot: 1.00-10
FPGA: 1.00
Username: