JPS QMT-1B User manual

Installation and Operation Manual
QMT-1B
IP Backhaul Remote
For
The SNV-12 Voter
JPS Interoperability Solutions
5800 Departure Drive
Raleigh, NC 27616
919-790-1011
Email: [e-mail] / [e-mail]
www.jpsinterop.com
JPS P/N 5200-300200 Revision 1.0 August 2020

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NOTICE
© 2020 JPS Interoperability Solutions. SNV-12, QMT-1B, SVM-2 and SVM-3
are all trademarks of JPS Interoperability Solutions, Inc.
JPS Interoperability Solutions reserves the right to make changes to the
equipment and specifications without prior notice.
CAUTION
Changes and modifications to this equipment not expressly approved by JPS
Interoperability Solutions could impair proper operation of the equipment
and/or could void user’s warranty.
JPS Interoperability Solutions
[phone]
[email protected]
[e-mail]
5800 Departure Drive
Raleigh, NC 27616

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Table of Contents
1GENERAL INFORMATION........................................................................................................................1-1
1.1 SCOPE.....................................................................................................................................................1-1
1.2 OVERVIEW .............................................................................................................................................1-1
1.3 SYSTEM REQUIREMENTS........................................................................................................................1-3
1.4 GENERAL NOTES....................................................................................................................................1-3
1.5 THE QMT-1B RADIO INTERFACE...........................................................................................................1-4
1.6 NETWORK INTERFACE............................................................................................................................1-4
1.7 SPECIFICATIONS.....................................................................................................................................1-5
1.8 EQUIPMENT AND ACCESSORIES SUPPLIED .............................................................................................1-6
1.9 DIFFERENCES BETWEEN THE QMT-1B AND THE QMT-1.......................................................................1-6
2INSTALLATION ...........................................................................................................................................2-1
2.1 GENERAL ...............................................................................................................................................2-1
2.2 UNPACKING AND INSPECTION................................................................................................................2-1
2.3 RESHIPMENT OF EQUIPMENT..................................................................................................................2-1
2.4 INSTALLATION OVERVIEW.....................................................................................................................2-2
2.5 INSTALLATION CONSIDERATIONS ..........................................................................................................2-3
2.5.1 Power Requirements.........................................................................................................................2-4
2.6 INSTALLATION CHECKLIST ....................................................................................................................2-4
2.7 REAR PANEL CONNECTORS....................................................................................................................2-4
2.7.1 DC Input Connector .........................................................................................................................2-4
2.7.2 Audio Level Adjustment....................................................................................................................2-4
2.7.3 Connection to Radio.........................................................................................................................2-4
2.7.4 Network Connection.........................................................................................................................2-6
2.7.5 RS-232 ..............................................................................................................................................2-6
2.7.6 Internal Jumper Configuration.........................................................................................................2-7
3CONFIGURATION.......................................................................................................................................3-1
3.1 GENERAL ...............................................................................................................................................3-1
3.2 QMT-1B CONFIGURATION SELECTIONS................................................................................................3-2
3.2.1 QMT-1B Name: ................................................................................................................................3-2
3.2.2 IP Address:.......................................................................................................................................3-2
3.2.3 Subnet Mask:....................................................................................................................................3-2
3.2.4 Gateway:...........................................................................................................................................3-3
3.2.5 QMT-1B RoIP Port: .........................................................................................................................3-3
3.2.6 QMT-1B Sync Port:..........................................................................................................................3-3
3.2.7 SVM-3 IP:.........................................................................................................................................3-3
3.2.8 SVM-3 RoIP Port: ............................................................................................................................3-3
3.2.9 SVM-3 Sync Port:.............................................................................................................................3-3
3.2.10 Squelch Type: ...................................................................................................................................3-3
3.2.11 COR Hangtime:................................................................................................................................3-3
3.2.12 COR Inhibit ......................................................................................................................................3-4
3.2.13 RX Input Level..................................................................................................................................3-4
3.2.14 Duplex:.............................................................................................................................................3-4
3.2.15 TX Output Level................................................................................................................................3-4
3.2.16 TX Delay:..........................................................................................................................................3-4
3.2.17 Restoring Factory Defaults ..............................................................................................................3-4
3.2.18 Store Setup Changes with SAVE Command.....................................................................................3-5
3.3 QMT-1B ACTIVITY LOG........................................................................................................................3-5
3.4 QMT-1B SECURITY...............................................................................................................................3-6
3.5 UPDATING THE QMT-1B SOFTWARE.....................................................................................................3-7

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4OPERATION ................................................................................................................................................. 4-1
4.1 GENERAL............................................................................................................................................... 4-1
4.2 OPERATION AT POWER-UP.................................................................................................................... 4-1
4.3 POWER LED .......................................................................................................................................... 4-1
4.4 LINK ACTIVE LED................................................................................................................................. 4-1
4.5 CHANNEL ACTIVE LED......................................................................................................................... 4-1
4.6 AUDIO INPUT LED ................................................................................................................................ 4-1
5QMT-1B TROUBLESHOOTING................................................................................................................ 5-1
6QMT-1B FAQ (FREQUENTLY ASKED QUESTIONS).......................................................................... 6-1
6.1 GENERAL............................................................................................................................................... 6-1

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List of Figures
FIGURE 1-1 SNV-12 VOTING SYSTEM WITH SVM-3 SITE VOTER MODULES AND QMT-1B REMOTES....................1-2
FIGURE 1-2 QMT-1B BASIC BLOCK DIAGRAM.........................................................................................................1-4
FIGURE 2-1 FRONT &REAR PANEL VIEWS...............................................................................................................2-3
FIGURE 3-1 QMT-1B INFORMATION PAGE ..............................................................................................................3-1
FIGURE 3-2 CONFIGURATION PAGE..........................................................................................................................3-2
FIGURE 3-3ACTIVITY LOG PAGE...............................................................................................................................3-5
FIGURE 3-4 SECURITY PAGE.....................................................................................................................................3-6
FIGURE 3-5 SOFTWARE UPDATE PAGE.....................................................................................................................3-7
List of Tables
TABLE 1-1 SPECIFICATIONS ................................................................................................................................1-5
TABLE 1-2 EQUIPMENT AND ACCESSORIES SUPPLIED.........................................................................................1-6
TABLE 2-1 BASIC INSTALLATION CHECKLIST.....................................................................................................2-4
TABLE 5-1 TROUBLESHOOTING TABLE...............................................................................................................5-1

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Glossary
Glossary
COR
Carrier Operated Relay
A signal from a receiver that gives a positive indication
that a carrier or signal is being received and that the
receiver is unsquelched. It has the same function as
Carrier Operated Squelch (COS).
COS
Carrier Operated
Squelch
See COR.
DHCP
Dynamic Host
Configuration Protocol
A method of automatically assigning an IP address to an
Ethernet device at startup time. This method conserves
IP addresses in networks where devices do not stay
connected permanently.
DSP
Digital Signal Processor
A type of microprocessor, which is optimized for signal
processing functions.
Idle Tone
Tones that are inserted into the audio stream when a
radio is squelched. Their absence indicates a receiver
unsquelched condition. Also called Pilot Tones.
IP
Internet Protocol
A protocol designed to allow communications between
computers on different networks.
LAN
Local Area Network
A group of computers and associated devices that share a
common communications line, typically within a small
geographic area.
NAT
Network Address
Translation
A scheme where multiple units can share one IP address,
usually behind a router.
Pilot Tone
See Idle Tone.
PTT
Push-to-talk
A signal to a radio transmitter, which controls the actual
transmission of radio frequency energy over the air. Also
called a keyline.
RoIP
Radio Over IP
A method of converting analog radio audio and flow
control signals into data and sending it to a distant unit to
be re-converted back into analog audio.
TCP
Transmission Control
Protocol
An additional layer to the Internet Protocol, which
ensures delivery of packets, sent across the network. It
can handle situations such as lost packets or packets
arriving out of order.
UDP
User Datagram Protocol
An additional layer to the Internet Protocol which does
not ensure delivery of packets, but which offers much
lower transmission overhead than TCP.
VoIP
Voice over Internet
Protocol
Also called Voice over Packet (VoP), a method of
sending voice communications across a digital network.
WAN
Wide Area Network
A network, which is spread out over a wider area, such
as around a city or state. It may include other public or
shared networks.

1General Information
1.1 Scope
This instruction manual provides the information necessary to install and operate the QMT-1B
IP Backhaul Remote. This manual assumes a basic understanding of the SNV-12 voter, analog
voter fundamentals, and the SVM-3 site voter module. See also the manual for the SNV-12 and
any manual addenda relative to the SVM-3 module.
1.2 Overview
The SNV-12 Voter has long been the leader in analog receiver voting. Prior to the introduction
of IP backhaul made possible by the QMT-1B working in concert with the SVM-3 modules, all
audio input into the SNV-12 was strictly synchronous, interfaced to SVM-2 modules. The
QMT-1B/SVM-3 pair allow voting receiver audio to be transported via non-synchronous IP.
To gain a good understanding of the system, it’s worth considering some of the technical
roadblocks that had to be overcome to make it work:
•An analog voter can function properly only if audio from all unsquelched voting
receivers is time-synchronized when it reaches the voter. Unfortunately for this
function, IP data transfer is not concerned with timing.
•Synchronization is needed because analog voters chose the best site by comparing FM
noise levels within a standard audio spectrum –at the same frequencies that carry
speech. High frequencies within the speech content alter the noise measurement, but all
balances out if audio is synchronized.
•Also, the voter may need to be able to switch to a new voted site during a field
transmission, and it must be able to do so without the listener experiencing any echoes
or missed syllables as the voter transitions from one site to another.
•Most codecs do a poor job of accurately transferring FM noise, simply because they are
not optimized to do so. This means that an SNV-12 module would not be able to do as
accurate a measurement on digitized RX audio as it does on analog RX audio
The SVM-3/QMT-1B pair resolves these potential problems:
The QMT-1B digitizes the audio for transport to the SVM-3 module, but also performs a pair
of other functions –it performs a Signal Quality (FM Noise) measurement on the analog audio
before digitization and also adds a time stamp.
This information is sent as metadata along with the digital audio packets. The SVM-3, in
concert with the SNV-12 voter, returns the audio to analog, uses the timestamp to
resynchronize the audio, and compares Signal Quality measurements to determine (and vote)
the best site.

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Figure 1-1 SNV-12 Voting System with SVM-3 Site Voter Modules and QMT-1B Remotes
QMT-1B remotes reside at the receiver site, one QMT-1B per receiver. By being placed at the
receiver, the QMT-1B can accurately measure the Signal Quality before the audio is encoded
into RoIP. The QMT-1B has an analog interface with the receiver/transceiver and can detect an
unsquelch condition by either a hardware COR line or by absence of an Idle Tone (sometimes
called a Pilot Tone). When the QMT-1B detects an Unsquelch condition, it begins taking
signal quality measurements of the receiver audio, adds time stamps, and encodes the audio
before sending the audio and metadata in a JPS-proprietary format.
The SVM-3 modules reside in the SNV-12 chassis. Each SVM-3 can connect to as many as
three QMT-1B remote units. The SNV-12 voter chassis can accommodate up to 12 SVM-3
modules providing a total of 36 receiver streams to the chassis.
SVM-3 modules can also coexist with SVM-2 modules in the same chassis, with some sites
passing analog RX audio to the voter, and others sending digitized audio via a QMT-1B.
When SVM-3 modules are added to an existing SNV-12 voter chassis, no changes are required
other than updating the CPM-3 Module to the latest firmware and then configuring the new
hardware. The CPM-1 Module cannot be used in a chassis equipped with SVM-3 modules.

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1.3 System Requirements
The IP network used with the SVM-3 modules must meet certain minimum requirements.
While the voter system may continue to work if some of these parameters are not met, the
overall system performance may be degraded.
For example, in order to time-synchronize audio signals, the quicker-to-arrive signals must be
delayed until the slowest one arrives. If the time variation is too long, normal communications
may be difficult to maintain.
For these reasons, the SVM-3 IP Backhaul is not intended to be run on public networks (i.e. the
Internet) because of widely varying performance. Note that public networks can be
overwhelmed during the types of incidents when proper performance is most vital.
The network that the SVM-3/QMT pair is used on must to meet the following specifications:
•100 Kbits/per second throughput per QMT-1B audio channel in each direction. 200
Kbps for a duplex channel.
•Packet loss less than 0.1%.
•Differential latency between RX sites less than 10ms.
•Jitter less than 5ms.
1.4 General Notes
Compatibility with Simulcast Systems
Outgoing QMT-1B audio CANNOT transport outgoing simulcast audio precisely or be
consistently timed to support simulcast transmissions. It is suitable for single transmit site
operation, TX steering, and multisite (different frequencies at different sites).
Site Totals
•An SNV-12 system with IP backhaul can consist of a single chassis, with up to 12
SVM-2 or SVM-3 modules. A larger system uses a Master Chassis that is connected to
and controls one or two Expansion Chassis for a total of 36 plug-in modules.
•Each SVM-2 module can serve only one remote voting site, connected by traditional
analog methods.
•Each SVM-3 module can serve up to three remote voting receiver sites and always
counts as three sites towards the maximum system site total of 60 (even if an SVM-3 is
interfaced to fewer than three receivers).
The main point to remember is that any combination of SVM-2 and SVM-3 modules can be
used in an Expanded system however the total site count cannot exceed 60 sites.

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1.5 The QMT-1B Radio interface
The QMT-1B employs the radio interface designed and optimized by JPS Interoperability
Solutions and therefore:
•Includes the radio interface DSP algorithms relevant to the IP Voting Backhaul
application.
•Can use any of the large number of custom interface cables, designed and optimized by
JPS Systems Engineering, covering over 300 different radio makes and models.
See Section 2.7.3 for complete information on the radio interface.
1.6 Network Interface
The QMT-1B is a 10/100BASE-T Ethernet device and each unit has a unique Ethernet address
and an RJ-45 physical interface jack. A 10/100BASE-T device operates at either 10 or 100
Mbps and interconnects to an Ethernet hub or switch using standard CAT 5 twisted pair cable,
also known as UTP. The maximum cable length between a QMT-1B and its hub port is 100
meters. The QMT-1B’s Ethernet port can be linked with virtually any LAN, WAN, or the
Internet, no matter which topology or cabling system is in use.
Figure 1-2 QMT-1B Basic Block Diagram