EndRun RTM3204 User manual
"Smarter Timing Solutions"
RTM3204
GPS Timing Module
User Manual
RTM3204 GPS Timing Module User Manual
RTM3204 GPS
Timing Module
User Manual
Preface
Thank you for purchasing the RTM3204 GPS Timing Module. Our goal in developing this product is
to bring you a precise time and frequency reference that will quickly, easily and reliably meet or ex-
ceed your system requirements. Your new RTM3204 is fabricated using the highest quality materials
and manufacturing processes available today, and will give you years of troublefree service.
About EndRun Technologies
EndRun Technologies is dedicated to the development and renement of the technologies required to
fulll the demanding needs of the time and frequency community.
Our innovative engineering staff, with decades of experience in the research and development of
receiver technology for the Global Positioning System (GPS), has created our window-mount GPS
antenna and extended hold-over oscillator-control algorithms.
The instruments produced by EndRun Technologies have been selected as the timing reference for
such rigorous applications as computer synchronization, research institutions, aerospace, network
quality of service monitoring, satellite base stations, and calibration laboratories.
EndRun Technologies is committed to fullling your precision timing needs by providing the most
advanced, reliable and cost-effective time and frequency equipment available in the market today.
Trademark Acknowledgements
IBM-PC, Linux, NotePad, Timeserv, UNIX, Windows NT, WordStar are registered trademarks of the
respective holders.
Part No. USM3204-0100-000 Revision 1
January 2008
Copyright © EndRun Technologies 2005-2008
RTM3204 GPS Timing Module User Manual
RTM3204 GPS Timing Module User Manual
About This Manual
This manual will guide you through simple installation and set up procedures.
Introduction – The RTM3204 GPS Timing Module, how it works, where to use it, its main features.
Basic Installation – How to connect, congure and test your RTM3204 GPS Timing Module.
Console Port – Description of the Linux console commands for use over the network and serial ports.
If you detect any inaccuracies or omissions, please inform us. EndRun Technologies cannot be held
responsible for any technical or typographical errors and reserves the right to make changes to the
product and manuals without prior notice.
Warranty
This product, manufactured by EndRun Technologies, is warranted against defects in material and
workmanship for a period of one year from date of shipment, under normal use and service. During
the warranty period, EndRun Technologies will repair or replace products which prove to be defec-
tive.
For warranty service or repair, this product must be returned to EndRun Technologies. Buyer shall
prepay shipping charges to EndRun Technologies and EndRun Technologies shall pay shipping
charges to return the product to Buyer. However, Buyer shall pay all shipping charges, duties, and
taxes for products returned to EndRun Technologies from another country.
Products not manufactured by EndRun Technologies but included as an integral part of a system (e.g.
peripherals, options) are warranted for ninety days, or longer as provided by the original equipment
manufacturer, from date of shipment.
Limitation of Warranty
The foregoing express warranty shall not apply to defects resulting from improper or inadequate
maintenance by Buyer or User, Buyer-supplied software or interfacing, unauthorized modication or
misuse, operation outside of the environmental specications for the product, or improper site prepa-
ration or maintenance.
TO THE EXTENT PERMITTED BY LAW, THIS WARRANTY AND REMEMDIES SET FORTH
ABOVE ARE EXCLUSIVE AND IN LIEU OF ALL OTHER WARRANTIES, REMEDIES AND
CONDITIONS WHETHER ORAL OR WRITTEN, STATUTORY, EXPRESS, OR IMPLIED. AS
PERMITTED BY APPLICABLE LAW, ENDRUN SPECIFICALLY DISCLAIMS THE IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
RTM3204 GPS Timing Module User Manual
RTM3204 GPS Timing Module User Manual
Warranty Repair
If you believe your equipment is in need of repair, call EndRun Technologies and ask for a customer
service agent. It is important to contact us rst as many problems may be resolved with a phone call.
Please have the serial number of the unit and the nature of the problem available before you call. If
it is determined that your equipment will require service, we will issue an RMA number. You will be
asked for contact information, including your name, address, phone number and e-mail address.
Ship the unit prepaid in the original container or a container of sufcient strength and protection to
EndRun Technologies. EndRun will not be responsible for damage incurred during shipping to us.
Be sure the RMA number is clearly identied on the shipping container. Our policy is to x or repair
the unit within 5 business days. If it is necessary to order parts or if other circumstances arise that
require more than 5 days, an EndRun service technician will contact you.
Repair After Warranty Expiration
If the warranty period has expired, we offer repair services for equipment you have purchased from
EndRun. Call and ask for a customer service agent. It is important to contact us rst as many prob-
lems may be resolved with a phone call. Please have the serial number of the unit and the nature
of the problem available before you call. If it is determined that the equipment has failed and you
want EndRun to perform the repairs, we will issue you an RMA number. Ship the unit prepaid in
the original container or a container of sufcient strength and protection to EndRun Technologies.
EndRun will not be responsible for damage incurred during shipping to us. Customer is responsible
for shipping costs to and from EndRun Technologies. Be sure the RMA number is clearly identied
on the shipping container. After the equipment has been received we will evaluate the nature of the
problem and contact you with the cost to repair (parts and labor) and an estimate of the time neces-
sary to complete the work.
Limitation of Liability
The remedies provided herein are Buyer’s sole and exclusive remedies. EndRun Technologies shall
not be liable for any direct, indirect, special, incidental or consequential damages, whether based on
contract, tort or any other legal theory.
RTM3204 GPS Timing Module User Manual
RTM3204 GPS Timing Module User Manual
RTM3204 GPS Timing Module User Manual
RTM3204 GPS Timing Module User Manual
Table of Contents
Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .i
About EndRun Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
Trademark Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
About This Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii
Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii
Limitation of Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii
Warranty Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .iii
Repair After Warranty Expiration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .iii
Limitation of Liability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .iii
Chapter One - Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Main Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Standard Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Secure Network Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Free FLASH Upgrades . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
GPS Timing-How It Works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Where to Use It . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Chapter Two - Basic Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Checking and Identifying the Hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Physical Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Performing an Initial Site Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Installing the RTM3204 GPS Timing Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Mount the RTM3204 GPS Timing Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Connecting and Configuring Ethernet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Configuring Ethernet with the Serial Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Connect the RS-232 Serial I/O Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Test the Serial Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Using netconfig to Set Up Your IP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Verify Network Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
RTM3204 GPS Timing Module User Manual
RTM3204 GPS Timing Module User Manual
Check Network Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Using Telnet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Using SSH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Connecting Instruments to the RTM3204 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Chapter Three - Control and Status Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
General Linux Shell Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Available User Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Detailed Command Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
accessconfig . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
cpuopts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
cpuoptsconfig . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
eraserootfs_1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
gpscaldelay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
gpsdynmode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
gpsrefpos . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
gpsstat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
gpstrkstat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
gpsversion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
gsyshwaddr . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
gsysosctype . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
gsyspasswd . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
gsysrootfs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
gsystimemode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
gsystimemodeconfig . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
gsysversion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
help . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
inetdconfig . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
netconfig . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
oscctrlstat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
pluginopts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
pluginoptsconfig . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
setgpscaldelay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
setgpsdynmode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
RTM3204 GPS Timing Module User Manual
RTM3204 GPS Timing Module User Manual
setgpsrefpos . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
updaterootflag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
upgradegps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
RS-232 Serial I/O Port Signal Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Appendix A - Time Figure-of-Merit (TFOM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Appendix B - Upgrading the Firmware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
What You Need To Perform the Upgrade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Performing the Linux Upgrade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Recovering from a Failed Upgrade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Performing the GPS Upgrade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Problems with the GPS Upgrade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Appendix C - Simple Network Management Protocol (SNMP) . . . . . . . . . . . . . . . 37
SNMPv3 Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Enterprise Management Information Base (MIB) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Invocation of the SNMP daemon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Quick Start Configuration -- SNMPv1/v2c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Configuring SNMPv1 Trap Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Configuring SNMPv2c Notifications and Informs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Configuration of SNMPv3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Appendix D - Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Linux Operating System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
OpenSSH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Appendix E - Timecode Formats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
IRIG-B122 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
IRIG-B123 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
IEEE-Standard 1344-1995 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
NASA-36 Bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
2137 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
IEEE-1344 Bit Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
RTM3204 GPS Timing Module User Manual
1
"Smarter Timing Solutions"
Chapter
One
Introduction
The RTM3204 is a derivative of our standard product, the Tycho GPS Frequency Reference. As such,
the software operating system interface will contain references to Tycho GPS. The RTM3204 GPS
Timing Module includes 1 PPS, 10M PPS, and IRIG-B as standard outputs plus an RS-232 serial
port. In addition, a network port which includes many protocols including TELNET, FTP, DHCP,
SNMP, and SSH is a standard feature.
The RTM3204 GPS Timing Module utilizes the GPS transmissions to precisely synchronize itself to
Universal Coordinated Time (UTC) to the 100-nanoseconds level of accuracy. The frequency of the
internal oscillator is disciplined to match the frequency of the UTC timescale to the low parts in 1013
level of accuracy over 24-hour observation intervals. The time and frequency outputs are coherent
after initial GPS synchronization, and synchronization is maintained via 20-bit DAC frequency con-
trol, rather than phase stepping, to provide excellent short-term stability.
Main Features
Overview
The Timing Module is composed of a Global Positioning System (GPS) time and frequency engine
integrated with an IBM-PC compatible fanless, convection-cooled 133 MHz CPU with integral
ethernet interface, an RS-232 serial port, a High-Performance Rubidium (Rb) oscillator, and a power
supply. Non-volatile storage of the embedded Linux operating system and the application software is
via FLASH memory.
Standard Features
In addition to sourcing precision 1PPS and 10MPPS timing references and an IRIG-B timecode out-
put, your Timing Module includes a serial port and a network port. The RTM3204 can be managed
via the network port or a local console on the RS-232 serial port. See Chapter 3 - Control and Status
Commands for more information.
Secure Network Interface
An ethernet port is provided as a standard feature of the RTM3204 GPS Timing Module with a wide
variety of protocols including SNMP with Enterprise MIB, SSH, TELNET, and FTP. Refer to Chap-
ter 2 - Basic Installation for information to help you set up your network interface. The inclusion of
SNMP v3 and SSH provides a very secure network interface and allows you to safely perform moni-
toring and maintenance activities over the network. Security-conscious users can also disable any or
all of the risky protocols such as Telnet, Time and Daytime. In addition, access via SSH, SNMP and
Telnet can be restricted to specic hosts. Refer to Appendix C - SNMP and Appendix D - Security
for further information.
Free FLASH Upgrades
Firmware and congurable hardware parameters are stored in non-volatile FLASH memory, so the
RTM3204 GPS Timing Module User Manual
2
CHAPTER ONE
Timing Module can be easily upgraded in the eld using FTP and TELNET or the local RS-232 serial
I/O port. Secure upgrades are possible via SSH and SCP. We make all rmware upgrades to our
products available to our customers free of charge. For rmware upgrade procedures refer to Appen-
dix B - Upgrading the Firmware.
GPS Timing-How It Works
The time and frequency engine in the RTM3204 receives transmissions from satellites that are operat-
ing in compliance with the Navstar GPS Interface Control Document (ICD) known as GPS-ICD-200.
It species the receiver interface needed to receive and demodulate the navigation and time transfer
data contained in the GPS satellite transmissions. The GPS navigation system requires a means of
synchronizing the satellite transmissions throughout the constellation so that accurate receiver-to-sat-
ellite range measurements can be performed via time-of-arrival measurements made at the receiver.
For the purposes of locating the receiver, measurements of the times-of-arrival of transmissions from
at least four satellites are needed. For accurate time transfer to a receiver at a known position, recep-
tion of the transmissions from a single satellite is sufcient.
The GPS system designers dened system time to be GPS time. GPS time is maintained by an
ensemble of high-performance cesium beam atomic frequency standards located on the earth’s
surface. GPS time is measured relative to UTC, as maintained by the United States Naval Observa-
tory (USNO), and maintained synchronous with UTC-USNO except that it does not suffer from the
periodic insertion of leap seconds. Such discontinuities would unnecessarily complicate the system’s
navigation mission. Contained in the data transmitted from each satellite is the current offset between
GPS time and UTC-USNO. This offset is composed of the current integer number of leap seconds
difference and a small residual error that is typically less than +/- 10 nanoseconds.
Each satellite in the constellation contains redundant cesium beam or rubidium vapor atomic frequen-
cy standards. These provide the timebase for all transmissions from each satellite. These transmis-
sions are monitored from ground stations located around the world and carefully measured relative to
GPS time. The results of these measurements for each satellite are then uploaded to that satellite so
that they may be incorporated into the data contained in its transmissions. The receiver can use this
data to relate the time-of-arrival of the received transmissions from that satellite to GPS time.
All of this means that during normal operation, the source of the timing information being transmit-
ted from each of the satellites is directly traceable to UTC. Due to the nature of the GPS spread
spectrum Code Division Multiple Access (CDMA) modulation scheme, this timing information may
be extracted by a well-designed receiver with a precision of a few nanoseconds. The GPS time and
frequency engine in the RTM3204 does just that.
Where to Use It
Since signals from the GPS satellites are available at all locations on the globe, you may deploy the
RTM3204 GPS Timing Module virtually anywhere. However, you must be able to install an antenna
with good sky visibility, preferably on the rooftop. Once continuously synchronized for at least 3
days, the Timing Module can maintain microsecond-level accuracy for about 24 hours without GPS
reception, by ywheeling on its Rubidium oscillator (Rb). If using the TCXO option this specica-
tion is greatly reduced - to the 10-millisecond level of accuracy.
3
"Smarter Timing Solutions"
RTM3204 GPS Timing Module User Manual
Chapter
Two
Basic Installation
This chapter will guide you through the most basic checkout and physical installation of your
RTM3204 GPS Timing Module. Subsequent chapters and appendices will give you the information
needed to congure your installation for the maximum performance in your operating environment.
Though some familiarity with Linux or other Unix-like operating systems would be helpful, it is not
essential. When operating your Timing Module with its standard network interface, basic familiarity
with TCP/IP networking protocols like ping, telnet and ftp is required.
Checking and Identifying
the Hardware
Unpack and check all the items using the shipment packing list. Contact the factory if anything is
missing or damaged. The RTM3204 GPS Timing Module shipment typically contains:
• RTM3204 GPS Timing Module (part # 3204-0101-000)
• RTM3204 GPS Timing Module User Manual (part #USM3204-0100-000)
• Basic cable kit including:
- RJ-45 to RJ-45 CAT-5 patch cable, 2 meters (part #0501-0000-000)
- DB9F-to-DB9F null-modem serial I/O cable (part #0501-0002-000)
• Antenna Kit including:
- GPS antenna
- Pipe/clamps for outside antenna mounting
- Inside window-mount kit
- 50’ TNC/BNC RG-59/U coaxial cable assembly
• Starter Kit including:
- 6” SMB/BNC antenna adaptor cable
- DC power connector and crimp pins
RTM3204 GPS Timing Module User Manual
4
CHAPTER TWO
5RTM3204 GPS Timing Module User Manual
BASIC INSTALLATION
Physical
Description
Sync LED This green LED ashes to indicate synchronization status.
Network LED This amber LED illuminates when the RTM32304 is connected to the
network and ashes when receiving or transmitting packets..
Alarm LED This red LED illuminates briey at power-up, and thereafter whenever
a serious fault condition exists.
Antenna Jack This SMB connector mates with the downlead cable from the external
antenna.
RS-232 Connector This DB-9M connector provides the RS-232 serial I/O console
interface to the RTM3204. This console allows the user to initialize
and maintain the RTM3204. See Chapter 3 - RS-232 Serial I/O Port
Signal Definitions for detailed information.
1PPS Jack This SMB connector provides the 1PPS TTL output. The pulse width
is normally 1 millisecond wide when shipped from the factory but can
be changed via console command “cpuoptscong”. Other selections
are 20 microseconds, 100 milliseconds and 500 milliseconds. See
signal denition in Appendix F - Specifications for the 1PPS output.
10MPPS Jack This SMB connector provides the 10MPPS TTL output. See signal
denition in Appendix F - Specifications for more information.
AM Code Jack This SMB connector provides the amplitude-modulated timecode
output. The timecode output is normally IRIG-B122 when shipped
from the factory, but can be changed via the console command
“cpuoptscong”. Other selections are IRIG-B123, IRIG-B IEEE-1344
compliant, NASA-36 and 2137. See signal denition in Appendix F
- Specifications for the AM Code output.
RTM3204 GPS Timing Module User Manual
4
CHAPTER TWO
5RTM3204 GPS Timing Module User Manual
BASIC INSTALLATION
DC Power Input Jack This 2-position jack provides connection to the DC power source. See
details in Appendix F - Specifications.
10/100Base-T Jack This rear-panel RJ-45 connector mates with the ethernet twisted pair
cable from the network.
Performing an
Initial Site Survey
Using the status LED indicators, it’s easy to nd out if your RTM3204 will work in your desired loca-
tion:
1. Mount the antenna on the roof using the supplied mounting hardware. Make sure that it is not
blocked by large metallic objects closer than one meter.
2. Connect the BNC plug on the end of the antenna cable to the supplied BNC jack to SMB plug
adapter cable. Connect the SMB plug end of the adapter cable to the antenna input jack on the
RTM3204 GPS Timing Module.
3. Connect the “+24VDC” terminal to the positive output of the DC power source. Connect the
“GND” terminal to the negative output of the DC power source. The DC power source voltage must
not exceed +32V. This unit will not operate if the +/- connections are reversed; however it will not be
damaged by a reverse connection. Note that the GND terminal is connected to the chassis inside the
unit.
Initially upon power up:
1. The unit will light the red Alarm Status LED for about ten seconds.
2. Then it will continuously light the green Sync Status LED.
3. Since your unit has a Rubidium oscillator (Rb), it will need 5 minutes to warmup before trying to
acquire a signal. When the unit locks onto a GPS signal and begins to decode the timing data and
adjust the local oscillator, the green Sync Status LED will ash very rapidly (about a 6 Hz rate) until
the data is fully decoded and the local oscillator is fully locked to the GPS frequency.
RTM3204 GPS Timing Module User Manual
6
CHAPTER TWO
7RTM3204 GPS Timing Module User Manual
BASIC INSTALLATION
4. Then the green Sync Status LED will pulse at precisely a 1 Hz rate, synchronized to UTC seconds,
with a short on duration relative to the off duration.
At this point, the GPS time and frequency engine has fully synchronized, and you may proceed to
permanently mount the RTM3204 and its antenna in their desired locations. If you are unable to
achieve GPS lock after 24 hours call Customer Support (1-877-749-3878) for assistance.
Installing the RTM3204
GPS Timing Module
Mount the RTM3204 GPS Timing Module
Mount the unit in the desired location. After mounting the unit and connecting the antenna cable,
verify that it still acquires and tracks a GPS signal. Refer to the baseplate drawing in Appendix F
- Specifications for the mounting hole locations.
CAUTION
Connecting and Configuring Ethernet
Connect one end of the CAT-5 patch cable supplied with your RTM3204 to the RJ-45 connector
labeled 10/100BASE-T. Connect the other end of the patch cable to your network through a ‘straight’
port on your hub. Do not connect it to a ‘crossover’ port on your hub.
By factory default, the RTM3204 will attempt to congure the ethernet interface automatically via
the Dynamic Host Conguration Protocol (DHCP). The RTM3204 will attempt to set the netmask,
its IP address, the IP address of the default gateway, the domain name and the IP addresses of any
nameservers, if the DHCP server is congured to provide them. You may optionally congure the
RTM3204 to also set its hostname via DHCP, if your DHCP server is congured to provide it. You
can do this by running a simple shell script called netconfig after your unit is up on the network.
If your network does use DHCP for host conguration, and you are in a hurry to get your RTM3204
up and running, you may procede to Verifying Network Conguration to make sure that the network
The RTM3204 internal temperature must not exceed 70˚C, as measured by the built-in temperature sensor
accessible via the “oscctrlstat” serial port command.
Internal temperature will remain in safe range if all conditions are met:
A. Base plate is in good thermal contact with external enclosure.
B. Ambient air temperature surrounding RTM3204 GPS Timing Module enclosure is < 50˚C.
C. Adequate clearance around RTM3204 enclosure allows for free-convection around cover.
D. No additional thermal sources via adjacent mechanical contact.
Condition A must be met. If condition B and/or C and/or D cannot be met as stated, use built-in tempera-
ture sensor to verify adequate operating margins.
RTM3204 GPS Timing Module User Manual
6
CHAPTER TWO
7RTM3204 GPS Timing Module User Manual
BASIC INSTALLATION
parameters were set up correctly. Otherwise, it is recommended that you read the following sections
on use of the RS-232 serial I/O port now, since they will help you in debugging any problems that
you may encounter with the automatic conguration via DHCP.
If your network does not use DHCP, you will need to congure your ethernet interface using the RS-
232 serial I/O port. The following sections contain brief descriptions on how to do that.
Configuring Ethernet with the Serial Port
To congure your ethernet interface with the serial port, after logging in as the root user, you must
run a simple shell script called netconfig from the bash shell prompt. This shell script will prompt
you for the needed information and perform some syntax checking on your inputs. Then it will create
or modify the appropriate les needed to congure the ethernet interface. The following sections will
guide you in setting up communications with the RTM3204 using its RS-232 serial I/O port.
Connect the RS-232 Serial I/O Port
You will need to use the RS-232 serial I/O port if your network does not support the Dynamic Host
Conguration Protocol (DHCP). In that case, you must be able to congure the RTM3204 network
parameters manually using the Linux console shell interface which is provided by this serial I/O port.
Under certain conditions, you may also need to use the RS-232 serial I/O port if you encounter a
problem while upgrading the rmware in your RTM3204 GPS Timing Module.
To test serial communications with the RTM3204 you will need either a VT100 compatible terminal
or a terminal emulation program running on your computer. We will refer to either of these as “termi-
nal” for the remainder of this instruction.
1. Disconnect power from the RTM3204.
2. Connect one end of the DB9F-to-DB9F null modem adapter cable to the serial I/O jack on the
RTM3204.
3. Connect the other end of the DB9F-to-DB9F null-modem adapter cable to the terminal. If the
serial I/O port on your terminal does not have a DB9M connector, you may need to use an adapter.
Refer to Chapter 3 - RS-232 Serial I/O Port Signal Definitions for details on the signal wiring. If
you are using a computer for your terminal, remember which port you are using because you will
need to know that in order to set up your terminal software.
Test the Serial Port
You must congure your terminal to use the serial I/O port you used in Connect the RS-232 Serial
I/O Port. You must also congure your terminal to use the correct baud rate, number of data bits,
parity type and number of stop bits. Be sure to turn off any hardware or software handshaking. The
settings for the RTM3204 are:
• 19200 is the Baud Rate
• 8 is the number of Data Bits
• None is the Parity
• 1 is the number of Stop Bits
After conguring these parameters in your terminal, apply power to the RTM3204. (The RTM3204
is a derivative of our Tycho GPS Frequency Reference. As such, all the Linux scripts will contain
RTM3204 GPS Timing Module User Manual
8
CHAPTER TWO
9RTM3204 GPS Timing Module User Manual
BASIC INSTALLATION
references to the Tycho GPS.) After about 20 seconds, your terminal should display a sequence of
boot messages similar to these:
***************************************************
* 6010-0040-000 Linux Bootloader v1.00 08/17/2004 *
***************************************************
Default root file system: FACTORY
To override and boot the UPGRADE partition type ‘UPGRADE’ within 5 seconds...
.....
These lines are the Linux bootloader boot prompt. This prompt will timeout after 5 seconds and
the Linux kernel and the factory default RTM3204/Tycho root le system will be loaded. When the
Linux kernel is loaded from FLASH memory into RAM a long list of kernel-generated, informational
messages is displayed as the kernel begins execution and the various device drivers are initialized:
Booting Linux with FACTORY root file system...
6010-0041-000 Linux Kernel v2.4.26-1 #0 Wed Aug 18 17:28:45 UTC 2004
BIOS-provided physical RAM map:
BIOS-88: 0000000000000000 - 000000000009f000 (usable)
BIOS-88: 0000000000100000 - 0000000002000000 (usable)
32MB LOWMEM available.
On node 0 totalpages: 8192
zone(0): 4096 pages.
zone(1): 4096 pages.
zone(2): 0 pages.
DMI not present.
Kernel command line: config=11000001 initjffs=0 console=ttyS0,19200 root=/dev/
mtdblock4 load_ramdisk=1 rw
Initializing CPU#0
Calibrating delay loop... 66.96 BogoMIPS
Memory: 30784k/32768k available (812k kernel code, 1596k reserved, 162k data, 68k
init, 0k highmem)
Checking if this processor honours the WP bit even in supervisor mode... Ok.
Dentry cache hash table entries: 4096 (order: 3, 32768 bytes)
Inode cache hash table entries: 2048 (order: 2, 16384 bytes)
Mount cache hash table entries: 512 (order: 0, 4096 bytes)
Buffer cache hash table entries: 1024 (order: 0, 4096 bytes)
Page-cache hash table entries: 8192 (order: 3, 32768 bytes)
CPU: AMD 486 DX/4-WB stepping 04
Checking ‘hlt’ instruction... OK.
POSIX conformance testing by UNIFIX
PCI: Using configuration type 1
PCI: Probing PCI hardware
PCI: Probing PCI hardware (bus 00)
Linux NET4.0 for Linux 2.4
Based upon Swansea University Computer Society NET3.039
Initializing RT netlink socket
Starting kswapd
JFFS2 version 2.1. (C) 2001 Red Hat, Inc., designed by Axis Communications AB.
Serial driver version 5.05c (2001-07-08) with MANY_PORTS SHARE_IRQ SERIAL_PCI enabled
ttyS00 at 0x03f8 (irq = 4) is a 16550A
ttyS01 at 0x02f8 (irq = 3) is a 16550A
ttyS02 at 0x03e8 (irq = 0) is a ST16654
ttyS03 at 0x02e8 (irq = 3) is a ST16654
sc520_wdt: CBAR: 0x800df000
sc520_wdt: MMCR Aliasing enabled.
sc520_wdt: WDT driver for SC520 initialised.
RAMDISK driver initialized: 16 RAM disks of 16384K size 1024 blocksize
pcnet32.c:v1.28 02.20.2004 [email protected]
PCI: Enabling device 00:0d.0 (0000 -> 0003)
RTM3204 GPS Timing Module User Manual
8
CHAPTER TWO
9RTM3204 GPS Timing Module User Manual
BASIC INSTALLATION
pcnet32: PCnet/FAST III 79C973 at 0x1000, 00 0e fe 00 00 33
tx_start_pt(0x0c00):~220 bytes, BCR18(9a61):BurstWrEn BurstRdEn NoUFlow
SRAMSIZE=0x1700, SRAM_BND=0x0800, assigned IRQ 12.
eth0: registered as PCnet/FAST III 79C973
pcnet32: 1 cards_found.
Tempus SC520 flash device: 1000000 at 2000000
Amd/Fujitsu Extended Query Table v1.3 at 0x0040
number of CFI chips: 1
Creating 7 MTD partitions on “Tempus SC520 Flash Bank”:
0x00000000-0x000e0000 : “Tempus kernel”
mtd: Giving out device 0 to Tempus kernel
0x000e0000-0x00100000 : “Tempus Lo BootLdr”
mtd: Giving out device 1 to Tempus Lo BootLdr
0x00100000-0x00200000 : “Tempus /boot”
mtd: Giving out device 2 to Tempus /boot
0x00200000-0x00300000 : “Tempus /logs”
mtd: Giving out device 3 to Tempus /logs
0x00300000-0x00900000 : “Tempus FACTORY rootfs”
mtd: Giving out device 4 to Tempus FACTORY rootfs
0x00900000-0x00fe0000 : “Tempus UPGRADE rootfs”
mtd: Giving out device 5 to Tempus UPGRADE rootfs
0x00fe0000-0x01000000 : “Tempus Hi BootLdr”
mtd: Giving out device 6 to Tempus Hi BootLdr
NET4: Linux TCP/IP 1.0 for NET4.0
IP Protocols: ICMP, UDP, TCP, IGMP
IP: routing cache hash table of 512 buckets, 4Kbytes
TCP: Hash tables configured (established 2048 bind 2048)
NET4: Unix domain sockets 1.0/SMP for Linux NET4.0.
mtdblock_open
ok
RAMDISK: Compressed image found at block 0
mtdblock_release
ok
VFS: Mounted root (ext2 filesystem).
Freeing unused kernel memory: 68k freed
INIT: version 2.76 booting
/etc/rc.d/rc.S: /bin: is a directory
mtdblock_open
ok
mtdblock_open
ok
Loading GPS
Fri Aug 20 00:53:54 2004 -0.707128 seconds
2004
Setting system time using hwclock
INIT: Entering runlevel: 3
Entering multiuser...
Attempting to configure eth0 by contacting a DHCP server...
At this point, if you do not have a DHCP server congured on your network the unit will time-out
and print these messages:
Tycho GPS DHCP Client was unable to find the DHCP Server!
Fix the problem and re-boot or set up static IP address
by running netconfig.
dnsdomainname: Host name lookup failure
(none)
Then these messages are printed, in either case:
Disabling IPv4 packet forwarding...
Starting daemons: syslogd klogd inetd
RTM3204 GPS Timing Module User Manual
10
CHAPTER TWO
11 RTM3204 GPS Timing Module User Manual
BASIC INSTALLATION
Starting the System Time daemon...
Starting the SNMP daemon...
Starting the system logfile manager...
Starting the system watchdog...woof!
During this process, the factory default TychoGPS_0 root le system is loaded from FLASH disk
to an 16MB ramdisk and the remainder of the boot process completes. At this point, the RTM3204/
Tycho login prompt is displayed:
********************************************************************************
* Welcome to Tycho GPS console on: gsys.your.domain
* Tue Feb 20 2001 21:47:03 UTC
********************************************************************************
gsys login:
Here you may log in as “gsysuser” with password “Praecis” or as the “root” user with password “en-
drun_1”. When logged in as “gsysuser”, you may check status information and view log les but you
will not be able to modify any system settings or view secure les. In order to perform system setup
procedures, which includes conguring the IP network settings, you must log in as the “root” user.
After correctly entering the password at this prompt,
password:
the sign on message is shown. It identies the host system as Tycho GPS and shows the software part
number, version and build date:
Tycho GPS 6010-0042-000 v 1.00 Wed May 9 14:17:44 UTC 2002
Tycho GPS (root@gsys:~)->
This last line is the standard RTM3204/Tycho shell prompt. The RTM3204/Tycho uses the bash
shell, which is the Linux standard, full-featured shell. After conguring the unit, you should change
the passwords using the gsyspasswd command issued from the shell prompt.
If you do not see characters displayed by your terminal program within 30 seconds after the unit is
powered up, you must troubleshoot your setup. An incorrectly wired cable or incorrect port setting
in your terminal emulation program are the most common problems. Refer to Chapter 4 - RS-232
Serial I/O Port Signal Definitions for the signal connections for the RTM3204.
NOTE
You must use a null-modem cable or adapter if you are connecting the RTM3204 to another computer
or other equipment configured as Data Terminal Equipment (DTE). The supplied cable is a null-modem
cable.
Once you have successfully established communications with the RTM3204, you may procede to
conguring the network parameters. Then you can communicate with the RTM3204 over the net-
work using telnet or ssh.
Using netconfig to Set Up Your IP
The following is a sample transcript which illustrates the use of netconfig. The entries made by
Table of contents
