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.

Interface Manual

2.5 BANDWIDTH REQUIREMENTS

The following tables identify the bandwidth requirements of the Four Wire Audio interface. It is referenced to the selected mode, active audio channels and UART data rate. When audio channels are dynamic (E & M controlled) the required bandwidth will vary depending on the active channels at that time.

The required bandwidth must be supported by the connected Radio Units for audio and UART data to pass successfully.

7 Channel Mode

Required Bandwidth (bps)

Enabled Audio Channels

No UART

9600 UART

(1)

0 Audio

19200

1 Audio

64000

73600

2 Audio

96000

105600

3 Audio

128000

137600

4 Audio

160000

169600

5 Audio

192000

201600

6 Audio

224000

233600

3 Channel Mode

Required Bandwidth (bps)

Enabled Audio Channels

No UART

9600 UART

(2)

0 Audio

19200

1 Audio

64000

2 Audio

96000

Fixed Channel Mode

Required Bandwidth (bps)

Enabled Audio Channels

No UART

9600 UART

(3)

0 Audio

N/A

1 Audio

32000

N/A

2 Audio

64000

N/A

NOTE(1) In 7 Channel Mode where at least one audio channel is active the additional bandwidth required for UART data is equal to the nominal UART data rate. When no audio channels are active the required bandwidth is twice the UART data rate as the Control Header is still required.

NOTE (2): In 3 Channel Mode the data bandwidth is carried in the control header. When no audio channels are active the required bandwidth is twice the UART rate otherwise no additional bandwidth is required. Nominal rates greater than 9600 bps are NOT supported.

NOTE (3): UART data is not supported in Fixed Channel Mode.

2.5.1 Radio Unit Bandwidth

The available Radio Unit data bandwidth is defined by the Radio Unit’s RF bandwidth and modulation settings, some examples are outlined in the following table.

Remaining bandwidth not utilised by the FWA interface may be utilised by other services supported by the Radio Units such as Ethernet data.

Net Available Radio Unit Bandwidth (bps)

16 QAM

64 QAM

25 kHz

129000

194000

12.5 kHz

65000

97000

Note: For a complete list please refer to the ’About that MiMOMax Data Rate’ whitepaper.

As an example Radio Units set to 25 kHz / 16 QAM connected to FWA interfaces with the CTRL selector set to 8 and a UART rate of 9600, would provide the following.

A single static audio channel. 9600 bps UART data. Up to 55400 bps of Ethernet data. A single additional dynamic audio channel limiting Ethernet data to 23400 bps when

active.

Alternatively if UART data was not utilised then the following would apply.

A single static audio channel. Up to 65000 bps of Ethernet data.

Two additional dynamic audio channels limiting Ethernet data to 33000 bps when one is active and 1000 bps when both are active.

Interface Manual

2.6 LATENCY

End-to-end latency is a combination of audio processing plus Radio Unit latency which is dependent on Radio Unit RF bandwidth and modulation settings.

Latency introduced by the Radio Units is dependent on the applied RF parameters. As an example radios with settings of 25 kHz and 16 QAM would provide an additional latency of

6ms. For a complete list please refer to the ‘MiMOMax Radio Installation and Operation

Guide’.

Four Wire Audio interface unit Latency (As would be achieved by direct connection between two Four Wire Audio interface units).

Audio latency : < 6ms (end-to-end audio delay for active channel) E&M latency : < 6ms (end-to-end delay for change of state) Data latency : < 1ms (end-to-end data delay)

Note: E&M Latency includes a de-bounce delay of 5ms where the E-Lead signal must be in a steady state for 5ms for that state to be recognised. Therefore audio will not be passed until the transition from inactive to active is recognised. Similarly audio will continue to be passed until the transition from active to inactive is recognised.

Adding the FWA interfaces and Radio Units latency figures will give an overall end-to-end latency.

As an example FWA interfaces connected to Radio Units set to 25 kHz and 16 QAM would provide the following.

Audio latency : 12 ms or better. EIA232 latency : 7 ms or better (NOTE: independent of interface word

timings). For Radio Units set up with Power on Demand (M-PoD) additional start up delays will be

experienced as the Air Interface is brought up. For further details please refer to the ‘MiMOMax Radio Installation and Operation Guide’.

3 POWER

3.1 OVERVIEW

The Four Wire Audio interface contains an isolated pre-regulator followed by local regulators to individual functional blocks.

The Isolated DC/DC Pre-Regulator accepts an input range of 12 to 48 volts DC and outputs a DC voltage with a nominal value of 10.5 volts DC.

The absolute minimum and maximum input voltages are 10 and 65 volt DC respectively with isolation of up to 1500 volts to board circuitry and unit ground being provided.

Where the Radio Units supply meets the above requirements it may also be used to power the FWA interface.

Isolated DC/DC

Pre-Regulator

(10.5 volts DC)

Board Level Regulation

DC Input -

Filtering

DC Input +

Filtering

10.5 volts DC

Unit

Ground

Circuit Overview

3.2 CABLING AND CONNECTIVITY

Image Showing Power Connected

Power Connector

(Phoenix Contact MSTBA 2,5 HC/2-G-5,08 Header)

Signal

Polarity

Description

NEGATIVE

0 volts

- volts

DC Input (Polarity must be observed)

POSITIVE

+ volts

0 volts

Interface Manual

4 AUDIO INTERFACES

4.1 OVERVIEW

The Four Wire Audio and E&M Signalling Interfaces are intended to provide point-to-point audio paths as would be required for back-haul linking of PMR base stations and trunking sites. Additionally the Four Wire Audio interfaces are able to be used for signalling (modems) as used by protection relays for power system protection and SCADA applications. The Four Wire Audio interface is able to act as a replacement for copper lines normally used for 4 wire audio and E&M signals (Note: Modems up to 4800 bps only are supported).

There are six audio channels incorporated into the Four Wire Audio interface where each audio channel is coded into the G726 32kbps ADPCM format. Dynamic (E&M controlled) and static (always up, E&M independent) channel operation is supported.

CODEC

PROCESSING

Transformer

(600 ohm)

Audio Data

Four Wire Audio Unit

Transformer

(600 ohm)

E&M

LOGIC

DC Block

M-Lead

E-Lead

Audio Output

Audio Input

Shield

Four Wire Audio

Port

Circuit Overview

Note: An E-Lead Signal is required for audio to pass unless a ‘Static’ or ‘Fixed’ channel configuration is selected.

4.2 AUDIO

Each audio port provides a balanced 600ohm transformer-isolated Four Wire Audio interface and an E&M signalling interface.

There is nominally 0.6dB ±0.3dB of gain in the audio path at 1kHz (This is NON configurable). The audio transport is achieved using a G726 32 kbps ADPCM vo-coder. This provides tone

transparent high quality audio. The input audio levels and frequency ranges are as follows.

-20 to +9 dBm (320 – 3500 Hz)

-20 to -10 dBm (65 - 320 Hz) Voice Frequency modems up to 4800 bps are supported.

Three modes of operation are supported.

7 channel mode where up to 6 audio channels and a single data channel are available. 3 channel mode where 2 audio channels and a single data channel are available. Fixed channel mode where 2 audio channels only are available.

The 3 and 7 channel modes provide for static (always up) or dynamic (E&M controlled) operation while fixed mode provides only for always up operation.

4.3 E & M SIGNALLING

For all dynamic audio channels an E-Lead signal is required for audio to pass through the system.

For ‘Static’ audio channels an E-Lead signal is NOT required and may be left unconnected. The M-Lead signal will always reflect the current output audio status of the port independent of the selected configuration.

A basic E&M signalling interface is provided utilising an opto-isolated switch for the output (M-Lead) and an opto-isolated current sense input (E-Lead).

The M-Lead will present an on resistance of < 40ohms when active and can support a load current of up to 100mA over the voltage range of 10V to 50V. The interface is polarity insensitive.

The E-Lead will detect a current of 5mA or greater as active. Internal current limiting is provided with a supported voltage range of 10V to 50V. The interface is polarity insensitive.

M Lead

sense (including voltage source)

Pin 7

Pin 8

Internal signal

Four Wire Audio Unit Customer Equipment

The FWA unit internally provides a switch across the M-Lead pins. The external sense circuit is required to provide its own voltage source which will allow a switch open or closed state to be sensed.

E Lead

10 to 50 volts DC

Pin 1

Pin 2

sense

Internal signal

sense

Customer EquipmentFour Wire Audio Unit

The FWA unit internally senses a DC voltage across the E-Lead pins. A DC voltage between 10v and 50v will allow the audio presented to the associated audio port to pass to the other end.

Interface Manual

4.4 CABLING AND CONNECTIVITY

The recommended cable for the audio connections is unshielded twisted pair.

Four Wire Audio Connector (RJ45 socket)

Signal

Description

E-Lead (SIGNAL)

Signalling Input

E-Lead (GND)

Signalling Input

Audio Input A

Audio to FWA from Connected Equipment

Audio Output A

Audio from FWA to Connected Equipment

Audio Output B

Audio from FWA to Connected Equipment

Audio Input B

Audio to FWA from Connected Equipment

M-Lead (SIGNAL)

Signalling Output

M-Lead (GND)

Signalling Output

A B

1 8

A B

RJ45 Plug (std and shielded)

RJ45 Socket

Stacked RJ45 Socket

RJ45 Pin Numbering

The ports labeled 1 through 6 are audio ports.

Image Showing Audio Cable Connected To Port 5.

4.4.1 Four Wire Audio Connectivity Examples

FWA-B

FWA-A RU RU

Audio

M_Lead

E_Lead

AudioAudio

M_Lead

E_Lead

Audio

HSSI

output

input

sense

output

input

Embedded Audio

N/C

Single Channel ‘Static’ Four Wire Audio Example.

Connectivity at FWA A and FWA B shows no E-Lead is required to allow audio to pass. Any audio presented at one end will be transported to the other.

The FWA A and FWA B graphics show the internal state of the M-Leads as indicating activity at all times.

Applicable to configuration selections 1 (channel 5), 5 (channel 5), and 6 (channels 5 and 6).

FWA-B

FWA-A RU RU

10 - 50 vDC

Audio

M_Lead

E_Lead

AudioAudio

M_Lead

E_Lead

Audio

0 vDC

HSSI

output

input

sense

output

input

Embedded Audio

open

closed

Single Channel with E & M signalling Four Wire Audio Example. The intention is to

highlight E-Lead functionality.

Connectivity at FWA A shows no E-Lead signal therefore audio presented does not appear at FWA B and the M-Lead is not energised.

Connectivity at FWA B shows a valid E-Lead signal and therefore audio passes to FWA A and the M-Lead is energised.

Applicable to configuration selections 0 (channels 1 through 6) and 3 (Supports 2 audio channels only, channels 5 and 6).

Interface Manual

FWA-B

Channel 2

Channel 3

Channel 1

FWA-A

Channel 1

Channel 2

0 vDC

10 - 50 vDC

Audio M_Lead E_Lead

Audio

10 - 50 vDC

Channel 3

10 - 50 vDC

0 vDC

Embedded Audio

closed

open

closed

Audio M_Lead E_Lead

Audio

Audio M_Lead E_Lead

Audio

Audio E_Lead M_Lead

Audio

Audio E_Lead M_Lead

Audio

Audio E_Lead M_Lead

Audio

Multi Channel With E & M Signalling Four Wire Audio Example. The Intention Is To

Show Differing Concurrent Configurations And The Resulting Audio.

Channel 1 shows E-Lead signal at FWA-A only allowing audio to pass from A to B only. Channel 2 shows E-Lead signal at FWA-A and FWA-B allowing audio to pass in both

directions (A to B and B to A). Channel 3 shows E-Lead signal at FWA-B only allowing audio to pass from B to A only. Applicable to configuration selections 0 (channels 1 through 6) and 3 (Supports 2 audio

channels only, channels 5 and 6).

5 DATA INTERFACES

A B

1 8

A B

RJ45 Plug (standard and shielded)

RJ45 Socket

Stacked RJ45 Socket

RJ45 Pin Numbering

5.1 ASYNCHRONOUS SERIAL (COM)

5.1.1 Overview

The COM port provides for EIA232 connectivity for end-to-end communications such as Inter Site Signalling for MPT systems. The supported data rate is 9600 bps.

While no error correction or retry capability is provided an internal 256 byte buffer preserves data during Radio Unit link anomalies and to support On-Demand (M-PoD) systems. A 200ms timeout is applied to prevent stale data persisting in the buffer.

232

Recieve Data

Transmit Data

COM (EIA232) Port

Shield

UART

Data

Four Wire Audio Unit

232

NOT USED

Circuit Overview

5.1.2 Cabling and Connectivity

Interface Manual

Image Showing COM (EIA232) Cable Connected

COM (EIA232) Connector (RJ45 socket)

Signal

Description

Transmit Data

Data Output From the FWA unit

Receive Data

Data Input To the FWA unit

Signal Ground

Signal Reference

NOT USED

(1)

Output (232 compatible)

NOT USED

(1)

Input (232 compatible)

1,4,8

Signal Ground

(1)

Not Used

Shield

Ground

Cable Shield

NOTE (1): For early Four Wire Audio Units (Serial Numbers between 2690065 and 2690109) these lines are not connected. Although internally connected on later units their use is not currently supported.

RJ45 – DB9 mapping

Signal (FWA unit)

Pin (RJ45)

Pin (DB9)

Tx Data

Rx Data

Signal GND

5.2 HIGH SPEED SERIAL INTERCONNECT (HSSI)

5.2.1 Overview

The High Speed Serial Interconnect is a full duplex interface with independent transmit and receive paths. FWA firmware prior to version 3.00 has a HSSI implementation where the clock and data are separate. Subsequent versions utilise a HSSI v2 implementation where the clock is embedded with the data. When HSSI v2 is utilised the clock signals provided by the physical interface are held in a static state and not used. Signalling levels over all HSSI connections conform to RS422.

The rate of FWA interface frames from the FWA interface to the Radio Unit is 4kHz except when no ports are active, in which case no frames are sent. Any sent frames will contain data for all enabled ports at that time.

A single HSSI payload from a Radio Unit to the FWA interface may contain 1 or more FWA interface frames. These contain the Audio and/or COM port data streams. The frame rate is dependent on the air interface configuration.

422

Recieve Clock

Recieve Data

Transmit Clock

Transmit Data

HSSI Port

Shield

HSSI v2 Framer

FWA Data

Four Wire Audio Unit

Circuit Overview

Interface Manual

5.2.2 Cabling and Connectivity

Image Showing HSSI Cable Connected. Note Shielded Plug.

The recommended cable for the HSSI connection is shielded twisted pair similar to Belden 1868E fitted with a shielded RJ-45 plug.

HSSI-A Connector (RJ45 socket)

Provides direct connection to MiMOMax Radio Unit. Utilises a one-to-one connecting lead (shielded cable and plugs).

Signal

Description

1,2

Transmit Data

Data Output To Radio Unit

7,8

Transmit Timing

Data Timing To Radio Unit

4,5

Receive Data

Data Input From Radio Unit

3,6

Receive Timing

Data Timing From Radio Unit

Shield

Ground

Cable Shield

For connection between the Radio Unit and FWA interface a one-to-one cable is used as defined in the following table. Radio Unit signals conform to the DCE convention while the Four Wire Audio interface signals conform to the DTE convention.

RU to FWA interface HSSI Cable

FWA unit : RJ45

Radio Unit : RJ45

Signal

Tx Clock A (output)

Tx Clock A (input)

Tx Clock B (output)

Tx Clock B (input)

Tx Data A (output)

Tx Data A (input)

Tx Data B (output)

Tx Data B (input)

Rx Clock A (input)

Rx Clock A (output)

Rx Clock B (input)

Rx Clock B (output)

Rx Data A (input)

Rx Data A (output)

Rx Data B (input)

Rx Data B (output)

Shield / GND

(1)

Body

Shield / GND

NOTE (1): At the Radio Unit GND is isolated from chassis ground. Connection of the ground at each end is required to ensure correct operation.

5.2.3 HSSI Cross Over

It is possible to connect 2 Four Wire Audio units back to back for testing where any enabled audio channel will pass unrestricted, some limitations apply to the COM port while the cross over is in place.

The Audio ports will behave as they would if the FWA units were part of a normal point to point system. If a channel is configured for E&M signalling then the E-Lead signal is similarly required for audio to pass.

The COM port is designed to accommodate on-demand operation so until it can be determined that the Air Interface is active, data is buffered. Therefore when testing the COM port with a cross over cable, an audio channel should also be active to ensure unrestricted data flow.

Image with two Four Wire Audio units connected by a HSSI crossover cable

HSSI X-Over Cable

Unit One : RJ45

Unit Two : RJ45

Signal

Tx Clock A 8 6

Rx Clock A

Tx Clock B 7 3

Rx Clock B

Tx Data A 2 5

Rx Data A

Tx Data B 1 4

Rx Data B

Rx Clock A 6 8

Tx Clock A

Rx Clock B 3 7

Tx Clock B

Rx Data A 5 2

Tx Data A

Rx Data B 4 1

Tx Data B

Shield / GND

Body

Shield / GND

Interface Manual

5.2.4 HSSI Loop Back

It is possible to create a HSSI loop back cable for testing that allows a FWA unit to be operated by itself where any enabled port will be directly looped back, this applies to both audio and COM ports although limitations apply to the COM port while the loop back is in place.

The Audio ports will behave as they would if the FWA unit was part of a normal point to point system. If a channel is configured for E&M signalling then the E-Lead signal is similarly required for audio to pass.

As the COM port will buffer the then delete data unless it can be determined that the air interface is active an audio channel should also be active to ensure unrestricted data flow when testing the COM port with a loop back cable.

Image Showing Loop Back Cable In Place.

HSSI Loop Back Connections

Signal

Pin (RJ45)

Signal

Tx Clock A

Rx Clock A

Tx Clock B

Rx Clock B

Tx Data A

Rx Data A

Tx Data B

Rx Data B

6 INSTALLATION

6.1 FITTING KIT

Description

Qty

MiMOMax Part Number

Mounting Bracket 1 302-06015-00

Screw M4x8 Pan Head

349-02059-00

Screw M4x10 Counter Sunk

349-02060-00

HSSI Cable

219-03337-00

Power connector and cable

219-03335-00

6.2 PHYSICAL

The image opposite shows the Four Wire Audio unit mounted in the rack mount tray.

The 2 M4x10 counter sunk screws attach the mounting bracket to the rack mount tray. These are visible in the opposite image.

The 4 M4x8 pan head screws are used to attach the FWA box to the mounting bracket and the rack mount tray. The 2 screws attaching the FWA box to the mounting bracket are visible in the opposite image.

6.3 RADIO UNIT CONNECTIVITY

Image Of Radio Unit And Four Wire Audio Interface Co-Located In The Rack Mount

Tray, With Shielded Connecting Cable In Place.

Interface Manual

The image opposite shows the shielded HSSI cable connected to the Synchronous Serial port of the Radio Unit.

6.4 RADIO UNIT CONFIGURATION

Radio Unit configuration is achieved through the CCMS web application. At this stage the FWA interface is unable to be configured from CCMS. For additional information regarding

Radio Unit configuration please refer to the ‘MiMOMax Radio Installation and Operation

Guide’. On the ‘Configure Serial Interfaces’ CCMS web page the mode needs to be set to HSSI2.

CCMS Screen Capture Showing HSSI2 Selection Following The Save Action.

Having selected and applied ‘HSSI2’ the radio will query the connected interface and display

any returned information and status. An example of the information and status can be seen in

figure ‘CCMS screen capture showing FWA interface status display’. The Radio will also

apply any items necessary to support the connected interface. The HSSI2 mode supports interfaces other than FWA.

CCMS Screen Capture Showing FWA Interface Status Display.

The CCMS Four Wire Audio status display is updated by selecting the ‘Refresh’ button. The

status will NOT update automatically.

Interface Manual

7 FIRMWARE UPGRADES

Firmware upgrades may only be performed at a MiMOMax Wireless service centre. If you require a firmware upgrade please contact MiMOMax Wireless directly for the location of the nearest service centre.

8 PRE FIRMWARE VERSION 3.00 CONSIDERATIONS

8.1 LED INDICATION

Only the LEDs in the following diagram (Power, HSSI and COM) provide an indication of operation. Audio Port LEDs do NOT provide any indication in products with firmware pre version 3.00.

Power LED (orange)

HSSI LED (green)

COM LED (green)

Four Wire Audio Interface Front IO

Power LED (orange): On when power applied. Off when no power is applied or a power fail condition exists.

HSSI LED (green): Nominally off, flashing on to indicate HSSI port activity (both transmit and receive). Note In certain modes the HSSI port is continuously active, as is the case when audio channels are configured for static or fixed operation.

COM LED (green): Nominally off, flashing on to indicate COM port activity (both transmit and receive).

8.2 AUDIO PORT OPERATION

For pre version 3.00 firmware the operating modes of the Audio Ports are as follows.

Audio Port

Operating Modes

One

7 channel mode ONLY in either static or dynamic operation.

Two

7 channel mode ONLY in either static or dynamic operation.

Three

7 channel mode ONLY in either static or dynamic operation.

Four

7 channel mode ONLY in either static or dynamic operation.

Five

3 and 7 channel modes in either static or dynamic operation. Fixed channel mode (no UART).

Six

3 and 7 channel modes in either static or dynamic operation.

Notable differences compared to version 3.00 and later are:

1. Only a single Fixed Channel is supported and the utilised port is different.

2. The ports utilised for 3 channel mode are different.

Interface Manual

8.3 CONFIGURATION

The following table outlines the operation of given selector settings for units with pre version

3.00 firmware.

Configuration Selector Definitions

Position

Description

Bandwidth Requirement (bps)

Dynamic 7 Channel Mode. 6 audio channels with E&M control (ports 1, 2, 3, 4, 5 & 6) plus a

single 9600 kbps UART channel. To enable Audio on a given channel an E-Lead signal is required.

0 - 233600

Fixed Channel Mode (UART data is ignored). Single static audio channel (Port 5). Audio on Port 5 (An E-Lead signal is NOT required).

32000 2

RESERVED

n/a

Dynamic 3 Channel Mode. 2 audio channels with E&M control (ports 5 & 6) plus a single 9600 kbps UART channel. To enable Audio on a given port an E-Lead signal is required.

0 – 96000 4

RESERVED

n/a

5, 6

Static 3 Channel Modes. Two options are available utilizing audio channels 5 and 6.

5: 1 Static audio channel (port 5), 1 dynamic audio channel (port 6) plus a single 9600 kbps UART channel.

64000 - 96000

6: 2 Static audio channels (ports 5 & 6) plus a single 9600 kbps UART channel.

96000

Static audio channels do NOT require an E-Lead signal; any additional supported dynamic channels may be used with an E-Lead signal.

RESERVED

n/a

8, 9, A, B, C, D

Static 7 Channel Modes. Six options are available utilizing all audio channels (1 through 6).

8: 1 Static audio channel (port 5), 5 dynamic audio channels (ports 6, 4, 3, 2 & 1) plus a single 9600 kbps UART channel.

64000 - 233600

9: 2 Static audio channels (ports 5 & 6), 4 dynamic audio channels (ports 4, 3, 2 & 1) plus a single 9600 kbps UART channel.

96000 - 233600

A: 3 Static audio channels (ports 5, 6 & 4), 3 dynamic audio channels (ports 3, 2 & 1) plus a single 9600 kbps UART channel.

128000 - 233600

B: 4 Static audio channels (ports 5, 6, 4 & 3), 2 dynamic audio channels (ports 2 & 1) plus a single 9600 kbps UART channel.

160000 - 233600

C: 5 Static audio channels (ports 5, 6, 4, 3 & 2), 1 dynamic audio channel (port 1) plus a single 9600 kbps UART channel.

192000 - 233600

D: 6 Static audio channels (ports 5, 6, 4, 3, 2 & 1) plus a single 9600 kbps UART channel.

224000 - 233600

Static audio channels do NOT require an E-Lead signal; any additional supported dynamic channels may be used with an E-Lead signal.

E, F

RESERVED

n/a

Notable differences compared to version 3.00 and later are:

1. Only a single Fixed Channel is supported and the utilised port is different.

2. The order of enabled ports is different for 3 and 7 channel modes.

3. The ports utilised for 3 channel mode are different.

8.4 HIGH SPEED SERIAL INTERFACE (VERSION 1)

For Firmware pre version 3.00 HSSI v1 is utilized and is not compatible with HSSI V2, as used with Firmware version 3.00 and later.

The nominal bit rate for the HSSI v1 interface is 1Mbps.

422

Recieve Clock

Recieve Data

Transmit Clock

Transmit Data

HSSI Port

Shield

HSSI v1 Framer

FWA Data

Four Wire Audio Unit

HSSI Circuit Overview

HSSI v1 utilises clock and data signals in each direction with the connections outlined in the above figure ‘Circuit Overview’ and the following table.

RU to FWA interface HSSI Cable

FWA unit : RJ45

Radio Unit : RJ45

Signal

Tx Clock A (output)

Tx Clock A (input)

Tx Clock B (output)

Tx Clock B (input)

Tx Data A (output)

Tx Data A (input)

Tx Data B (output)

Tx Data B (input)

Rx Clock A (input)

Rx Clock A (output)

Rx Clock B (input)

Rx Clock B (output)

Rx Data A (input)

Rx Data A (output)

Rx Data B (input)

Rx Data B (output)

Shield / GND

(1)

Body

Shield / GND

NOTE (1): At the Radio Unit GND is isolated from chassis ground. Connection of the ground at each end is required to ensure correct operation.

Interface Manual

8.5 RADIO UNIT CONFIGURATION

Radio Unit configuration is achieved through the CCMS web application. A radio link utilising adaptive modulation (M-CAM) is NOT supported. On the ‘Configure Serial Interfaces’ CCMS web page the mode needs to be set to HSSI.

Serial Interfaces CCMS Web Page Showing HSSI Selection

For further details on Radio Unit configuration please refer to the document ‘MiMOMax Radio Installation and Operation Guide’.

9 TECHNICAL DATA

Audio

Connector

RJ45

Number of Channels

Input Range to Unit

-20 dBm to +9dBm (320 – 35000 Hz)

-20 dBm to -10dBm (65 – 320 Hz)

Insertion Loss

+0.6 dB (±0.3 dB) @ 1000 Hz

Frequency Range

65 Hz to 3500 Hz

Nominal Impedance

600 ohm

Latency

(1)

<6ms

E&M Signaling

Connector

RJ45 (co-located with audio)

Type

current sense input / switch output

Latency

(1)

<6ms

(2)

UART (EIA232) Data

Connector

RJ45

Data Rate

9600 (Set in Firmware and NOT user configurable)

Latency

(1)

<1ms

(3)

Network (HSSI) Port

Connector

RJ45

Protocol

Proprietary for direct connection to MiMOMax Radio Units

Power

Connector

Detachable screw terminal

Type

Isolated DC/DC converter

Isolation

1500 volts

Nominal Input Voltage

12 to 48 VDC

Operational Input voltage

10 to 64 VDC

Power

<1.5 W

Mechanical Dimension

38mm x 140mm x 258mm (H x W x D)

Environmental

Temperature (operational)

- 25 ºC to 60 ºC

Humidity (operational)

4% to 100% (per EN 300 019 sec. 3.3 & 4.2H)

Altitude (operational)

0 to 3000m

Environmental Protection

IP20 (Indoor use only)

NOTE (1): Quoted latencies are for back-to-back connected FWA units. For audio channels this is for audio following channel initialisation. The total end-to-end latency will require addition of latency through the Radio Units. Channel establishment is NOT included.

NOTE (2): E & M latency includes a 5ms de-bounce delay. NOTE (3): For the UART the quoted delay does not account for the interface transmission delay (e.g. the

time to transfer a word between the connected UARTs at either end).

Mimomax Four Wire Audio Interface Manual

Specifications and Main Features

Frequently Asked Questions

User Manual