Mimomax Four Wire Audio Interface 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

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.

TABLE OF CONTENTS

1 OVERVIEW............................................................................................................................. 5

1.1 HIGH SPEED SERIAL INTERFACE (HSSI) .......................................................... 6

1.2 AUDIO ............................................................................................................ 6

1.3 DATA .............................................................................................................. 6

1.4 CONFIGURATION ............................................................................................. 6

2 OPERATION 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

3 POWER ................................................................................................................................ 15

3.1 OVERVIEW .................................................................................................... 15

3.2 CABLING AND CONNECTIVITY ......................................................................... 15

4 AUDIO INTERFACES ........................................................................................................... 16

4.1 OVERVIEW .................................................................................................... 16

4.2 AUDIO .......................................................................................................... 16

4.3 E & M SIGNALLING ........................................................................................ 17

4.4 CABLING AND CONNECTIVITY ......................................................................... 18

4.4.1 Four Wire Audio Connectivity Examples ..................................................... 19

5 DATA 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

6 INSTALLATION .................................................................................................................... 27

Interface Manual

6.1 FITTING KIT ................................................................................................... 27

6.2 PHYSICAL ..................................................................................................... 27

6.3 RADIO UNIT CONNECTIVITY ........................................................................... 27

6.4 RADIO UNIT CONFIGURATION ......................................................................... 28

7 FIRMWARE UPGRADES ..................................................................................................... 30

8 PRE 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

9 TECHNICAL DATA .............................................................................................................. 35

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)

Interface Manual

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

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)

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).

(Shielded RJ45)

Audio Port One

Available in 3 and 7 channel modes (either static or dynamic operation). Available in Fixed channel mode.

(Shielded RJ45)

Audio Port Two

Available in 3 and 7 channel modes (either static or dynamic operation). Available in Fixed channel mode.

(Shielded RJ45)

Audio Port Three

Available in 7 channel Mode ONLY (either static or dynamic operation).

(Shielded RJ45)

Audio Port Four

Available in 7 channel Mode ONLY (either static or dynamic operation).

(Shielded RJ45)

Audio Port Five

Available in 7 channel Mode ONLY (either static or dynamic operation).

(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 ELead. 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.

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

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)

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

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

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.

2.4 RADIO UNIT ADVANCED FEATURES

The MiMOMax Radio Units have advanced operating modes which the FWA interface supports.

2.4.1 On-Demand

In the On Demand mode the radio link will go into standby when not required. To support this feature the FWA interface must be configured such that all audio channels are dynamic (under E&M control).

When no audio channels are active and no data is being passed the FWA interface will allow the Radio Link to go into standby. Similarly when an audio channel becomes active or data is ready to be sent the FWA interface will inform the radio units and thereby bring up the Radio Link.

Buffering is provided for COM port data such that it is retained for a period to allow the Radio Link to come up. Following a 200ms timeout period if the Radio Link is still down the data is deleted.

2.4.2 Adaptive Modulation

Adaptive Modulation allows the Radio Link to scale its data throughput to that supported by the radio channel. Under normal operation any scaling back of the data is temporary as it is in response to a transient degradation in the radio channel.

The Four Wire Audio interface will prioritise enabled audio channels based on available bandwidth. The audio ports priority is sequential with port 1 having the highest priority and port 6 the lowest. The relationship between the operating RF mode and supported channels is determined by comparing the bandwidth requirement tables in section 2.5 (Bandwidth Requirements) with radio unit bandwidth as outlined in the document ‘MiMOMax Radio Installation and Operation Guide’.

For example: if the audio ports 1, 3 and 5 were enabled and the current radio bandwidth only supported 2 ports then port 5 would be disabled while ports 1 and 3 would operate as normal. Once the link bandwidth was restored all 3 ports would operate as normal.

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Mimomax Four Wire Audio Interface Manual

Specifications and Main Features

Frequently Asked Questions

User Manual