IRT Electronics MMM-4230, MMX-4230 Instruction Book

4230-mmm & 4230-mmx.ib.rev4.doc Page 1 of 17 17/10/2007

IRT Eurocard

Types MMM-4230 & MMX-4230

4 Channel ASI to G.703 Multiplexer / De-Multiplexer

I R T Electronics Pty Ltd A.B.N. 35 000 832 575

26 Hotham Parade, ARTARMON N.S.W. 2064 AUSTRALIA
National: Phone: [phone] Fax: [phone]
International: [phone] [phone]
Email: [e-mail]
Web: www.irtelectronics.com

Designed and manufactured in Australia

IRT can be found on the Internet at:

http://www.irtelectronics.com

4230-mmm & 4230-mmx.ib.rev4.doc Page 2 of 17 17/10/2007

IRT Eurocard

Types MMM-4230 & MMX-4230

4 Channel ASI to G.703 Multiplexer/De-Multiplexer

Instruction Book

Table of Contents

Section Page

Operational Safety 2
General Description 3
Technical Specifications 4
Configuration 5

Link settings 5
Switch settings 6

45 Mb version 6

Variable Bandwidth – Channel Allocation Selection A 7

34 Mb version 8

Installation 9

SMU-4000 Installation 10

Figure 1: SMU-4000 module 10
RS-422 pin assignments 11
The RS-422 standard 12
Front and rear layouts 13

SNMP – What Is It? 14
Maintenance & Storage 16
Warranty & Service 16

Equipment return 16

Drawing List Index 17

This instruction book applies to units later than S/N 0504001.

Operational Safety:

WARNING

Operation of electronic equipment involves the use of voltages and currents that
may be dangerous to human life. Note that under certain conditions dangerous
potentials may exist in some circuits when power controls are in the OFF position.
Maintenance personnel should observe all safety regulations.

Do not make any adjustments inside equipment with power ON unless proper
precautions are observed. All internal adjustments should only be made by suitably
qualified personnel. All operational adjustments are available externally without the
need for removing covers or use of extender cards.

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IRT Eurocard

Types MMM-4230 & MMX-4230

4 Channel ASI to G.703 Multiplexer/De-Multiplexer

General Description

The MMM-4230 and MMX-4230 are part of a family of data transcoders for converting between the commonly
used MPEG2 Transport Stream formats for video distribution in the broadcast industry.

With the MMM-4230 up to four ASI and one RS422 data signals can be multiplexed together and converted into a
framed or unframed DS3 signal for transmission down a single 45 Mb/s G.703 line.

The MMX-4230 converts and demultiplexes the 45 Mb/s G.703 signal back into the original four ASI signals (at
their original rates) and the RS422 data signal.

An on board switch on the MMM-4230 sets the maximum data rates for each ASI input allowing the efficient use of
the available bandwidth and for protection against overuse of the bandwidth by the other channels. Total maximum
data rate up to 43.5 Mb/s is allowed. Temporary packet stuffing is used to automatically bring the rate up to
45 Mb/s.

Inputs are automatically equalised for lengths of up to 300m of Belden 8281 or equivalent cable.
RS422 9600 Baud uni-directional data may also be sent on the same link.
Front panel indication and relay alarm on the MMM-4230 transmitter shows if there is an input data rate violation.

Corresponding alarm on the MMX-4230 receiver shows a loss of G.703 input.
An optional Simple Network Management Protocol (SNMP) plug-in module is available for remote monitoring of

input and output status, control and alarm states.
The MMM-4230 and MMX-4230 are designed to fit IRT’s standard Eurocard frames as well as IRT’s 4000 series

frame for use with IRT’s SNMP system and may be used alongside any other of IRT’s analogue or digital
Eurocards.

Note: Also available in a 34 Mb/s G.703 version. See “Configuration - switch settings” section for configuration
table.

Standard features:

• Up to 4 ASI and 1 Data stream on one 45 Mb/s G.703 link

• Input rate stuffing to 45 Mb/s G.703 rate

• Selectable input maximum data rates

• Automatic Input equalisation up to 300m

• Suitable for Single Frequency Network (SFN) use

• Optional SNMP plug-in monitoring and control module

• Eurocard format

MMM-4230 MMX-4230

Mux

&

Signal

Processing

ASI-1

Input

G.703

Output

ASI-2

Input

ASI-3

Input

DATA

Input

Processing

&

De-Mux

ASI-1

Output

G.703

Input

ASI-2

Output

ASI-3

Output

DATA

Output

ASI-4

Output

ASI-4

Input

SNMP

SNMP

4230-mmm & 4230-mmx.ib.rev4.doc Page 4 of 17 17/10/2007

Technical Specifications

MMM-4230:

Inputs:

Type 1 4 x ASI-C 75Ω, 800 mVp-p, BNC connector.
Maximum Data Rate 40.1 Mb/s (for 188 byte packet),

43.5 Mb/s (for 204 byte packet).

Channel Data Rate Assignments I/P1 I/P2 I/P3 I/P4 (Mb/s)
(for 188 byte packet length signals) 40 + 0 + 0 + 0
35 + 5 + 0 + 0
30 + 10 + 0 + 0
25 + 15 + 0 + 0
20 + 20 + 0 + 0
30 + 5 + 5 + 0
25 + 10 + 5 + 0
20 + 15 + 5 + 0
20 + 10 + 10 + 0

13.5 + 13.5 +13.5 + 0
Variable
20 + 10 + 5 + 5
15 + 15 + 5 + 5
15 + 10 + 10 + 5
10 + 10 + 10 + 10

Type 2 RS422 9600 Baud Uni directional.

Output:

Type 1 x G.703, 75Ω BNC connector.
Electrical Characteristics B3ZS encoded.
Data Rate 44.736 Mb/s.

Alarm Output: Contact closure on error, loss of power.

MMX-4230:

Input:

Type 1 x G.703, 75Ω BNC connector.
Electrical Characteristics B3ZS encoded.
Data Rate 44.736 Mb/s.

Outputs:

Type 1 4 x ASI-C 75Ω, 800 mVp-p, BNC connector.
Data Rate same as MMM-4230 input rate.
Type 2 RS-422 9600 Baud Uni directional.

Alarm Output: Contact closure on loss of G.703 input, loss of power.
Power Requirements 28 Vac CT (14-0-14) or ±16 Vdc.

Power consumption 6.5 VA.

Other

Temperature range 0 - 50° C ambient.
Mechanical Suitable for mounting in IRT 19" rack chassis with input, output and power

connections on the rear panel.
Finish Front panel Grey, silk-screened black lettering & red IRT logo.
Rear assembly Detachable silk-screened PCB with direct mount connectors to Eurocard and

external signals.
Dimensions 6 HP x 3 U x 220 mm IRT Eurocard.
Optional Accessories SNMP plug-in module for use with 4000 series frame fitted with SNMP

“Agent”.

NOTE: Also available in a 34 Mb/s G.703 version.

Due to our policy of continuing development, these specifications are subject to change without notice.

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Configuration

Link settings

MMM-4230 CONFIGURATION INFORMATION

Program 4230mmm.tdf LK6A Installed

LK1 IN When using Switch 1 position A ‘Variable Bandwidth’, if the frequency of an input that has an

assignment of 26.8Mb/s falls below 13.4 Mb/s then the assignment will revert to 13.4Mb/s. All other
conditions mentioned in the Variable Bandwidth section still apply.

OUT The frequency resetting mentioned above does not occur.

LK2 IN Existing Reed Solomon encoding on ASI streams will pass through system.
If no RS is present on the input then RS encoding is added.
OUT Reed Solomon encoding added to input ASI steams regardless of whether existing RS encoding exists

or not.

LK3 Not used.

LK4

*

IN Output G.703 signal will be “framed”.

OUT Output G.703 signal will be “unframed”.

LK5

*

IN Output “unshaped” (recommended for output drive lengths > 68m (225ft)).

OUT Output “shaped” (recommended for output drive lengths < 68m (225ft)).

LK7 Installing this link will terminate the RS-422 data line.

Note: * Not applicable for 34 Mb/s (E3) version.

MMX-4230 CONFIGURATION INFORMATION

LK1 IN Allows instantaneous changes in channel bandwidth allocation as required by the “Variable” Data

Assignment.

OUT Error concealment is applied to the packet distribution.

LK2 IN Output packet size is always 204 byte and will contain Reed Solomon code regardless of

corresponding MMM-4230 input packet size.

OUT Output packet size matches that of corresponding MMM-4230 input packet size.

LK3 IN Outputs can be individually disabled by SNMP remote control. Note that this requires SNMP

functionality within IRT’s SNMP frame.

OUT All outputs are always enabled. SNMP functionality not required.

LK4

*

IN For input G.703 signal that is “framed”.

OUT For input G.703 signal that is not “framed”.

LK5 IN Input G.703 equaliser not enabled.
OUT Input G.703 equaliser enabled.

LK10 Installing this link will terminate the RS-422 data line.

Note: * Not applicable for 34 Mb/s (E3) version.

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Switch settings

MMM-4230 45Mb version:

The MMM-4230 Multiplexer works in a channel protection mode. The necessity for protection arises if the data rate
of the inputs exceeds the maximum allowable for an MMM-4230 Transmitter (43.5Mb/s). Without protection all
used channels would suffer errors. With protection, the available data rate can be divided among the input channels
and if a channel tries to exceed its allocation only that channel is adversely affected.

A switch, SW1, on the MMM-4230 sets the maximum data rates for each ASI input.

For 204 byte packets the following allocation is possible.

Channel Data Rate Assignment

Switch 1 Position

I/P 1 I/P 2 I/P 3 I/P 4

0 43.5 - - ­1 38.26 5.46 - ­2 32.8 10.93 - ­3 27.33 16.4 - ­4 21.86 21.86 - ­5 32.8 5.46 5.46 ­6 27.33 10.93 5.46 ­7 21.86 16.4 5.46 ­8 21.86 10.93 10.93 -

9 14.6 14.6 14.6 ­A Variable
B 21.86 10.93 5.46 5.46
C 16.4 16.4 5.46 5.46
D 16.4 10.93 10.93 5.46
E 10.93 10.93 10.93 10.93

F Remote

For 188 byte packets the following is true –

Channel Data Rate Assignment

Switch 1 Position

I/P 1 I/P 2 I/P 3 I/P 4

0 40.10 - - -

1 35.26 5.03 - -

2 30.22 10.07 - -

3 25.18 15.11 - -

4 20.14 20.14 - -

5 30.22 5.03 5.03 -

6 25.18 10.07 5.03 -

7 20.14 15.11 5.03 -

8 20.14 10.07 10.07 -

9 13.47 13.47 13.47 ­A Variable
B 20.14 10.07 5.03 5.03
C 15.11 15.11 5.03 5.03
D 15.11 10.07 10.07 5.03
E 10.07 10.07 10.07 10.07

F Remote

Note: For Channel allocation selection by SNMP control the Data Rate switch (SW1) must be set to “F”.
These data rates are only the maximum

allowed for the channel. Any lower rate may be used.

SW1

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Variable Bandwidth – Channel Allocation Selection A:

For 188 byte packets the following allocation is possible –

Channel Data Rate Assignment

I/P 1 I/P 2 I/P 3 I/P 4

40.2 - - -

26.8 13.4 - -

26.8 - 13.4 -

26.8 - - 13.4

13.4 13.4 13.4 -

13.4 13.4 - 13.4

13.4 - 13.4 13.4

- 40.2 - -

13.4 26.8 - -

- 26.8 13.4 -

- 26.8 - -

- 13.4 13.4 13.4

- - 40.2 -

13.4 - 26.8 -

- 13.4 26.8 -

- - 26.8 13.4

- - - 40.2

13.4 - - 26.8

- 13.4 - 26.8

If only one channel is present then the total bandwidth is allocated to that channel.

If two channels are present and one exceeds a rate of 13.4 Mb/s then that channel will be assigned 26.8 Mb/s and
the other 13.4 Mb/s. However, input 1 has priority over inputs 2, 3, & 4, input 2 has priority over inputs 3 & 4, and
input 3 has priority over input 4. So even if, say, channel 2 has an input rate above 13.4 Mb/s and then input 1’s rate
also increases above 13.4 Mb/s, then input 1 will be assigned the bandwidth of 26.8 Mb/s whilst input 2’s will be
relegated to 13.4 Mb/s. Once a channel has been assigned a ba nd wid th o f 2 6. 8Mb/s it will retain the allocation until
either its input signal is removed, or until a channel with higher priority requires 26.8Mb/s allocation, or there are
any three channels connected.

If three channels are present they will each be assigned 13.4 Mb/s.

If four channels are present then channel 4 will not get any b andwidth.

The error concealment in the MMX-4230 will not allow an instantaneous change in channel allocation, so this
should be disabled when using the above option by installing link LK1.