Mimomax Four Wire Audio Interface User manual

Four Wire Audio Interface
Manual
2013
This document contains proprietary information that
must not be provided or copied to third parties without
express permission from MiMOMax Wireless Limited

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© MiMOMax 2013 Four Wire Audio
Interface Manual
MiMOMax Wireless Ltd
Four Wire Audio Interface Manual 2013
Disclaimer
While precaution has been taken in the preparation of this literature and it is believed to be correct at the time of
issue, MiMOMax Wireless Ltd assumes no liability for errors or omissions or for any damages resulting from the
use of this information. Due to a policy of continuous technical improvement, the contents of this document and
any specifications contained therein are subject to revision and may change without notice.

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© MiMOMax 2013 Four Wire Audio
Interface Manual
TABLE OF CONTENTS
1OVERVIEW.............................................................................................................................5
1.1 HIGH SPEED SERIAL INTERFACE (HSSI)..........................................................6
1.2 AUDIO ............................................................................................................6
1.3 DATA..............................................................................................................6
1.4 CONFIGURATION .............................................................................................6
2OPERATION AND CONFIGURATION ...................................................................................7
2.1 INDICATORS....................................................................................................7
2.2 CONNECTIVITY................................................................................................8
2.3 CONFIGURATION .............................................................................................8
2.3.1 7 Channel Mode.............................................................................................8
2.3.2 3 Channel Mode.............................................................................................9
2.3.3 Fixed Channel Mode......................................................................................9
2.3.4 Configuration Selector Access.......................................................................9
2.3.5 Configuration Selector Definitions ...............................................................10
2.4 RADIO UNIT ADVANCED FEATURES ................................................................11
2.4.1 On-Demand .................................................................................................11
2.4.2 Adaptive Modulation ....................................................................................11
2.5 BANDWIDTH REQUIREMENTS .........................................................................12
2.5.1 Radio Unit Bandwidth ..................................................................................13
2.6 LATENCY ......................................................................................................14
3POWER................................................................................................................................15
3.1 OVERVIEW....................................................................................................15
3.2 CABLING AND CONNECTIVITY.........................................................................15
4AUDIO INTERFACES...........................................................................................................16
4.1 OVERVIEW....................................................................................................16
4.2 AUDIO ..........................................................................................................16
4.3 E&MSIGNALLING........................................................................................17
4.4 CABLING AND CONNECTIVITY.........................................................................18
4.4.1 Four Wire Audio Connectivity Examples .....................................................19
5DATA INTERFACES ............................................................................................................21
5.1 ASYNCHRONOUS SERIAL (COM)....................................................................21
5.1.1 Overview......................................................................................................21
5.1.2 Cabling and Connectivity.............................................................................21
5.2 HIGH SPEED SERIAL INTERCONNECT (HSSI)..................................................23
5.2.1 Overview......................................................................................................23
5.2.2 Cabling and Connectivity.............................................................................24
5.2.3 HSSI Cross Over .........................................................................................25
5.2.4 HSSI Loop Back...........................................................................................26
6INSTALLATION....................................................................................................................27

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Interface Manual
6.1 FITTING KIT...................................................................................................27
6.2 PHYSICAL .....................................................................................................27
6.3 RADIO UNIT CONNECTIVITY ...........................................................................27
6.4 RADIO UNIT CONFIGURATION.........................................................................28
7FIRMWARE UPGRADES .....................................................................................................30
8PRE FIRMWARE VERSION 3.00 CONSIDERATIONS.........................................................31
8.1 LED INDICATION ...........................................................................................31
8.2 AUDIO PORT OPERATION...............................................................................31
8.3 CONFIGURATION ...........................................................................................32
8.4 HIGH SPEED SERIAL INTERFACE (VERSION 1).................................................33
8.5 RADIO UNIT CONFIGURATION.........................................................................34
9TECHNICAL DATA ..............................................................................................................35

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© MiMOMax 2013 Four Wire Audio
Interface Manual
1 OVERVIEW
Four Wire Audio Box
The Four Wire Audio (FWA) interface is a full duplex audio solution with optional E & M
signalling intended for connectivity to equipment requiring an analogue audio interface e.g.
Voice Frequency (VF) modems, or radio systems such as analogue base stations.
Additionally a single EIA232 (UART) interface is provided for end-to-end site communications
at 9600 baud.
The MiMOMax Four Wire Audio interface is provided for by an add-on Network Interface Box
(NIB) which communicates directly with a MiMOMax Radio Unit. The Four Wire Audio
interface is able to be co-located with the Radio Unit in the standard rack mount tray.
Four Wire Audio Solution Overview
The MiMOMax Radio Units plus Four Wire Audio interfaces provide a complete point to point
audio solution where low latency high quality audio is required. When paired with Radio Units
utilizing 16 QAM in a 25 kHz channel, 12 ms latency or better is achievable (A detailed
latency discussion is available in section 2.6)

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© MiMOMax 2013 Four Wire Audio
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1.1 HIGH SPEED SERIAL INTERFACE (HSSI)
The High Speed Serial Interface (HSSI) is a proprietary synchronous serial interface
developed by MiMOMax to enable Network Interface Box’s to be connected to Radio Units.
The connection allows user and configuration data to pass between the two units. User data
presented to the Radio Unit passes to the remote end and ultimately to the terminating
Network Interface Box.
1.2 AUDIO
Up to 6 fully independent transmit and receive audio paths (4 wire connections) are provided
with E&M signalling. Two configuration options are provided, one where an E-Lead signal is
required for audio to pass (dynamic), and the other where the selected audio channels are in
an always up configuration (static).
The audio transport is achieved using a G726 32 kbps ADPCM Vo-coder to offer low latency,
tone transparent high quality audio. The operational frequency range is 65 Hz to 3500 Hz.
1.3 DATA
A single EIA232 compliant data port is provided at 9600 baud (8N1 no hardware flow control)
for inter-site communications. The UART configuration is set in firmware so a special order is
required for an alternate rate. Note that the UART is disabled in Fixed Channel Mode.
1.4 CONFIGURATION
Configuration is provided for by an on board selector switch. Several configuration options are
available including a range of static and dynamic combinations. These are described in
section 2.3.5.
Radio Unit Four Wire Audio Interface Co-Located in the 2U Rack Tray

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Interface Manual
2 OPERATION AND CONFIGURATION
Power LED (orange)
HSSI LED (green) COM LED (green)
Audio Port LEDs (green)
Four Wire Audio Interface Front IO
2.1 INDICATORS
Connector located LEDs provide for indication of unit operation. The unused LEDs are
disconnected and will remain off.
Power LED (orange): On when power applied. Off when no power is applied or a power
fail condition exists.
HSSI LED (green): On when a valid connection is detected. Flashing off to indicate
HSSI port transmit or receive activity and off otherwise
COM LED (green): Nominally off, flashing on to indicate COM port activity (both transmit
and receive).
Audio LEDs (green): On when either the ports transmit or receive path is active and off
otherwise.
(Note: The Audio Port LEDs will remain off if no HSSI link is
available)

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Interface Manual
2.2 CONNECTIVITY
Connector
Description
12 –48 Vdc
Input Power
HSSI-B
(Shielded RJ45)
Not Used (Intended for future enhancements)
HSSI-A
(Shielded RJ45)
Connection to Radio Unit
COM
(Shielded RJ45)
UART Port (EIA232 end-to-end site communications)
Available in 3 and 7 channel Modes (NOT available in Fixed Mode).
1
(Shielded RJ45)
Audio Port One
Available in 3 and 7 channel modes (either static or dynamic operation).
Available in Fixed channel mode.
2
(Shielded RJ45)
Audio Port Two
Available in 3 and 7 channel modes (either static or dynamic operation).
Available in Fixed channel mode.
3
(Shielded RJ45)
Audio Port Three
Available in 7 channel Mode ONLY (either static or dynamic operation).
4
(Shielded RJ45)
Audio Port Four
Available in 7 channel Mode ONLY (either static or dynamic operation).
5
(Shielded RJ45)
Audio Port Five
Available in 7 channel Mode ONLY (either static or dynamic operation).
6
(Shielded RJ45)
Audio Port Six
Available in 7 channel Mode ONLY (either static or dynamic operation).
2.3 CONFIGURATION
Three basic modes of operation are provided; 7 channel, 3 channel and fixed channel. Each
of these modes will define the number of simultaneous audio channels able to operate.
Additionally channels may operate in either dynamic (E & M signalled) or static (always up)
configurations.
Static audio channels pass continuously without an E-Lead signal and the M-Lead signal is
continuously activated. Static channels have a set bandwidth requirement. Dynamic audio
channels are E-Lead controlled where the corresponding M-Lead reflects the state of the E-
Lead. Dynamic channels only consume bandwidth when set as active by the E-Lead signal.
The bandwidth requirement of any selection must be compatible with the supporting radio link
(see Section 2.5).
2.3.1 7 Channel Mode
(6 audio channels plus a data channel plus Control Header)
Audio channels are either always on (static) or controlled via E&M signalling (dynamic). E&M
signalling requires an E-Lead signal for audio to pass.
The data channel passes COM port data as required with the nominal throughput defined by
the UART rate.

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2.3.2 3 Channel Mode
(2 audio channels plus a data channel plus Control Header).
To provide for better bandwidth utilization in situations where only 1 or 2 audio channels are
required the Control Header is reordered to provide for the UART data channel.
Audio channels are either always on (static) or controlled via E&M signalling (dynamic). E&M
signalling requires an E-Lead signal for audio to pass.
The data channel passes COM port data as required with the nominal throughput defined by
the UART rate.
2.3.3 Fixed Channel Mode
(Audio channels only, No data, No Control Header).
To minimize bandwidth requirements only audio data is passed end to end. This places the
limitations of no COM port data and only 2 audio channels. Both channels when enabled
conform to the static configuration as no data passes to indicate their state.
2.3.4 Configuration Selector Access
Observe EMC precautions whenever enclosure is open.
To access the Configuration Selector the unit should first be powered down. The lid may then
be removed to gain access to the selector. Using a suitable tool the selector may be rotated
to the desired selection. The units at both ends of the link must be in compatible modes.
The configuration selector is a single rotary encoder placed on the PCB as shown in the
following image.
Configuration
Selector
Location of Configuration Selector

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Interface Manual
2.3.5 Configuration Selector Definitions
The following table lists all options available through the on board selector and the associated
bandwidth requirement ranges.
Position
Description
Bandwidth
Requirement
(bps)
0
Dynamic 7 Channel Mode.
6 audio channels with E&M control. Audio ports 1, 2, 3, 4, 5
and 6 are available.
Single 9600 kbps UART channel.
0 - 233600
1, 2
Fixed Channel Mode.
COM port data is NOT supported.
1: Single fixed audio channel (port 1).
32000
2: Dual fixed audio channels (ports 1 & 2)
64000
3
Dynamic 3 Channel Mode.
2 audio channels with E&M control. Audio ports 1 and 2 are
available.
Single 9600 kbps UART channel.
0 –96000
4
RESERVED
n/a
5, 6
Static 3 Channel Modes.
5: 1 Static audio channel (port 1), 1 dynamic audio channel
(port 2) plus a single 9600 kbps UART channel.
64000 - 96000
6: 2 Static audio channels (ports 1 & 2) plus a single 9600
kbps UART channel.
96000
7
RESERVED
n/a
8, 9, A,
B, C, D
Static 7 Channel Modes.
8: 1 Static audio channel (port 1) plus 5 dynamic audio
channels (ports 2, 3, 4, 5 & 6) plus a single 9600 kbps UART
channel.
64000 - 233600
9: 2 Static audio channels (ports 1 & 2) plus 4 dynamic audio
channels (ports 3, 4, 5 & 6) plus a single 9600 kbps UART
channel.
96000 - 233600
A: 3 Static audio channels (ports 1, 2 & 3) plus 3 dynamic
audio channels (ports 4, 5 & 6) plus a single 9600 kbps
UART channel.
128000 - 233600
B: 4 Static audio channels (ports 1, 2, 3 & 4) plus 2 dynamic
audio channels (ports 5 & 6) plus a single 9600 kbps UART
channel.
160000 - 233600
C: 5 Static audio channels (ports 1, 2, 3, 4 & 5) plus 1
dynamic audio channels (port 6) plus a single 9600 kbps
UART channel.
192000 - 233600
D: 6 Static audio channels (ports 1, 2, 3, 4, 5 & 6) plus a
single 9600 kbps UART channel.
224000 - 233600
E, F
RESERVED
n/a
Static audio channels do NOT require an E-Lead signal. Any additional supported dynamic
channels may be used with an E-Lead signal.
Fixed Channel Mode channels do NOT require an E-Lead signal.