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Matrix

Matrix Detail Book

Matrix Details, Diagrams and Descriptions

The Comrex Matrix in its basic form is a digital audio transmission device for analog telephone lines. The Matrix allows wideband, broadcast quality audio over normal "toll quality" telephone circuits.

Matrix Features

Here's a short list of the Matrix's POTS Codec features:

  • Full duplex FM quality (15 kHz) audio bandwidth at connect rates of 24 kb/s and above.
  • Full duplex audio scales from 12.7 kHz to 4.7 kHz at connect rates of 21.6 kb/s to 9.6 kb/s.
  • Separate "Voice Mode" allows 7 kHz audio with a 300 BAUD ancillary data channel and extra forward error correction.
  • Easy to use dialing and configuring interface.
  • Available in portable or rackmount chassis.
  • Automatically connects at highest possible rate supported by telephone connection.
  • Monitors line quality and renegotiates should line degrade.
  • Ability to dial and answer telephone calls in "Plain Telephone Mode." Useful when a line is not adequate for codec use.

  • Ability to "store and forward" 9 3/4 minutes of audio. A full fidelity feed may be recorded and sent over a low bitrate circuit to be played later in non-real time.
  • Two tally closures (one is latching and closes on connection and one is a momentary closure triggered by the user).
  • Ability to work with a Comrex HotLine or Vector POTS codec.
  • Ability to store 19 telephone numbers and last number dialed in nonvolatile memory.
  • Short coding delay (100 ms) for seamless two-way conversation.
  • Accessory slot accommodates optional modules, adapting Matrix Portable for use on ISDN or GSM circuits or as a coupler hybrid.
  • Optional battery runs Matrix for up to 7 hours.

Portable Unit Includes

  • 2 channel microphone mixer (1 channel is mic/line selectable).
  • Additional fixed level tape input.
  • 1 headphone output (adjustable mix of send and receive audio).
  • 1 balanced line level audio output (adjustable mix of send and receive audio).
  • Rugged, lightweight plastic chassis with handle.

Rackmount Unit Includes

  • Space efficient 1U rack.
  • Internal universal AC power supply.
  • Balanced line level audio in/out.
  • Ability to dial on contact closure.
  • Ability to remotely control contact closure.
  • Remote control of functions through TCP/IP protocol.

Audio Frequency Response (Portable & Rackmount)

*At all connect rates and in all modes, the low frequency response is 20 Hz. The high end response is at right:

Connect Rate Music Mode Voice Mode HotLine Mode
9.6 kb/s 4.7 kHz 4.7 kHz n/a
12 kb/s 6 kHz 6 kHz 4.5 kHz
14.4 kb/s 7 kHz 7 kHz 5.4 kHz
16.8 kb/s 7 kHz 7 kHz 5.6 kHz
19.2 kb/s 11.2 kHz 7 kHz 5.8 kHz
21.6 kb/s 12.7 kHz 7 kHz 6.5 kHz
24 kb/s 14 kHz 7 kHz 7 kHz
26.4 kb/s 14 kHz 7 kHz 8 kHz
28.8 kb/s 14 kHz 7 kHz 8.6 kHz
31.2 kb/s 14 kHz 7 kHz 9.3 kHz
33.6 kb/s 14 kHz 7 kHz 10 kHz

Matrix Portable Surface Diagram

Matrix Portable - Top Surface Diagram
Portable - Top Surface Diagram

  1. Bicolor Input Level Indicator
    This provides an indication of the audio level being fed into the Matrix inputs.
  2. Battery Function Light
    When this red LED is illuminated, the Matrix is operating on battery power.
  3. Rear Panel
    Audio connectors are located on the rear panel. 
  4. Input Level Control 1
    This knob controls the input audio level for audio channel 1.
  5. Input Level Control 2
    This knob controls the input audio level for audio channel 2.
  6. Headphone Jack
    This is a 3-conductor 1/4 inch headphone jack suitable for most stereo headphones.
  7. Headphone Level Adjustment
    This knob controls the headphone jack audio level. This includes all local and return audio. Adjust this knob until a comfortable listening level is achieved on the headphones. Note: A ratio of local or return audio levels may be set up using the Output Mix Adjustment. (See 9 below.)
  8. XLR Line Level Output Adjustment
    This knob controls the Output audio level. This includes all local and return audio. Adjust this knob for desired output level. Note: A ratio of local or return audio levels may be set up using the Output Mix Adjustment. (See 9 below.)
  9. Output Mix Adjustment
    This knob determines the mix/ratio of local versus return audio. Adjust this knob until a comfortable mix of local and return audio is achieved. Turning the knob counterclockwise gives more local audio. Turning the knob clockwise gives more return audio.
  10. Dialing Keypad
    Use this keypad to place calls. Numbers may also correspond to menu options.
  11. Function Keypad
    These keys provide "one touch" access for several major functions such as quick dialing and hang up. Some of the keys also have secondary functions, noted under the key.
  12. Side Panel
    Power, phone lines and data connections are made on this panel. 
  13. Ring/Carrier Detect (CD) Indicator
    When the Matrix receives an incoming call, this light will flash to indicate the line ringing. When the modem inside the Matrix is connected to another compatible codec, this light will be on steadily.
  14. Ready Indicator
    This is a signal from the digital audio decoder which signifies it has locked onto the incoming digital audio signal. This will usually light up a few seconds after connection and go out if a retrain is necessary or if the codec "loses sync" for any reason. A contact closure which follows this indication is available on the rear panel.
  15. Backlit LCD
    Displays all status and menu options.

Matrix Portable - Rear Panel Diagram

Matrix Portable - Rear Panel Diagram
  1. XLR Line Level Output
    This 3-pin male XLR output provides a mix of codec return and local audio from the Matrix. It is a balanced, line level audio feed, adjustable via the Line Output and Output Mix knobs on the top surface. This output is suitable for connection to a mixer, PA system or additional headphones.
  2. Input 2 Microphone Connector
    This 3-pin female XLR connector is designed to accept a balanced, microphone level audio feed. The input level for this channel is adjustable via the knob shown in #5 of the Top Surface diagram.
  3. Input 1 Mic/Line Connector
    This 3-pin female XLR connector is designed to accept a balanced, microphone or line level audio feed. This input level is adjustable via the top surface control shown in #4 of the Top Surface diagram. The level is selectable between nominal mic or line level. (See #19 below.)
  4. Input 1 Mic/Line Switch
    This switch determines whether audio input 1 is configured to receive a microphone level (-70 to -40 dBu) or line level (-10 to +10 dBu) audio input.
  5. Tape Input -10 dBu Mini Jack
    This 1/8 inch mini tape input is designed to accept an unbalanced, -10 dBu fixed audio feed. This allows easy connection to a minidisc or DAT player.

Matrix Portable - Side Panel Diagram

Matrix Portable - Side Panel Diagram
  1. Tel Line Jack
    This RJ-11 jack is for attaching the telephone line from the outside world to the Matrix. Be careful what you plug into here. Some PABXs provide currents which can damage the Matrix.
  2. Tel Set Jack
    This RJ-11 jack is for attaching an external telephone to the Matrix. This can be useful for dialing complicated numbers with lots of pauses and special codes. It can also serve to provide an audible "ring" when an incoming call is received.
  3. Multipurpose Port
    Female DB-9 connector through which flash upgrades can be performed. This port will also be used for future features.
  4. Power On/Off Switch
    0 = off, 1 = on. These markings are screened directly on the rocker switch.
  5. Power Connector
    This is a 5-conductor DIN type connector designed to mate with the Matrix power supply module. Be sure to attach only the power supply provided from Comrex here.
  6. Contact Closure
    This mini jack provides a momentary dry contact closure which triggers closed when the Matrix is on-line and the far end sends a CC command via the keypad.
  7. Ready Closure
    This mini jack provides a latching dry contact closure when the digital audio decoder achieves synchronization with an incoming digital audio signal. This contact is closed when the green Ready light below the LCD display is illuminated and is released when the Ready light goes out.

Matrix Rack - Front Panel Diagram

Matrix Rackmount - Front Panel Diagram
  1. Backlit LCD
    Displays all status and menu options.
  2. Function Keypad
    These keys provide "one touch" access for several major functions such as quick dialing and hang up. Some of the keys also have secondary functions which are noted by the key.
  3. Ring/Carrier Detect (CD) Indicator
    This keypad is used to place calls, either in Matrix or POTS Mode. Numbers may also correspond to menu options.
  4. Dialing Keypad
    This keypad is used to place calls, either in Matrix or POTS Mode. Numbers may also correspond to menu options.
  5. Ready Indicator
    This is a signal from the digital audio decoder which signifies it has locked onto the incoming digital audio bitstream. This will usually light up a few seconds after connection and go out if a retrain is necessary or if the codec "loses sync" for any reason. A contact closure which follows this indication is available on the rear panel.
  6. VU Meter
    This provides an indication of the audio level being fed into the Matrix. It doesn't mirror the receive audio in any way.

Matrix Rack - Rear Panel Diagram

Matrix Rackmount - Rear Panel Diagram
  1. IEC 320 Power Connector / Fuse Outlet
    This is an IEC connector for the main power. The Matrix works on any worldwide AC power from 100-240 VAC.
  2. Output Connector
    This is a 3-pin male XLR connector with balanced, line level output audio. The rackmount Matrix does not mix any local audio into this output. The only audio heard here will be coming from the far end. The level of this output is selectable via menu options.
  3. Input Connector
    This is a 3-pin female XLR connector designed to accept balanced, line level audio. This audio sent into the encoder on the Matrix is reflected on the front panel VU meter. The nominal level of this input is selectable via the menu system.
  4. Aux Closure
    This mini jack input provides the ability to dial the phone number stored in the Qdial 01 position when the contact is closed. The Aux Closure may also be used for future features, including select remote control functions.
  5. Ready Contact Closure
    This mini jack provides a latching dry contact closure when the digital audio decoder achieves synchronization with an incoming digital audio signal. This contact is closed when the green Ready light below the LCD display is lighted and is released when the Ready light goes out.
  6. Multipurpose Port
    Flash upgrades may be performed through this port. Future uses of this port include connection for a TCP\IP remote controller for all Matrix functions.
  7. CC Send Control
    This mini jack allows the user remote control of the CC button on the front keypad. When the Matrix is on-line, a closure here will send a signal to close the CC receive relay at the far end. An asterisk will appear in the upper right corner of the far end Matrix, indicating that the signal has been received.
  8. CC Receive Closure
    This mini jack is a momentary dry contact closure which triggers closed when the Matrix is on-line and the far end sends the CC command via the keypad.
  9. Tel Line Jack
    This RJ-11 jack is for attaching the telephone line from the outside world to the Matrix. Be careful what you plug into here. Some PABXs contain voltages which can damage the Matrix.
  10. Tel Set Jack
    This RJ-11 jack is for attaching an external telephone to the Matrix. This can be useful for dialing complicated numbers with lots of pauses and special codes. It can also serve to provide an audible "ring" when an incoming call is received.
  11. Accessory Option Back Plate
    This plate can be removed if the optional ISDN board is installed. Connectors for ISDN will be placed in the voids behind this plate.

Matrix Portable Specifications

All specifications are subject to change

Audio connections

  • One XLR mic input—adjustable level
  • One XLR mic/line input—adjustable level
  • Auxiliary mini-jack line tape input—fixed level
  • Headphone output—adjustable mix of send and receive audio
  • Balanced XLR line level audio out—adjustable mix of send and receive audio

Other connections

  • Telephone line and telephone set: RJ-11 6-pin modular jacks (2)
  • Contact closures: 2-conductor mini-jacks (2)
    • Ready: Latching dry contact closure when Matrix Portable encoder is synchronized to far-end Comrex decoder
    • Enter: Momentary dry contact closure activated by button push on Comrex codec
  • Auxiliary data port: DB-9
  • Accessory connection: 25-pin D
  • Power: 5 pin mini-DIN

Audio input levels

  • Mic input: -70 to -40 dBu @ 2 KΩ
  • Line input: -10 to +10 dBu @ 20 KΩ
  • Tape input: -10 dBu (fixed) @ 10 KΩ

Audio output levels:

  • Line level out: +12 dBu maximum @ 100Ω
  • Headphone out: .5 watt @ 100Ω

Audio Performance

  • POTS:
    Audio performance varies with phone circuit conditions
    • Full duplex FM quality (15 kHz) audio bandwidth at connect rates of 24 kbps and above
    • Full duplex audio scales from 12 kHz to 5 kHz at connect rates of 21.6 kbps to 9.6 kbps
    • Selectable “Voice Mode” allows 7 kHz audio with a 300 bps ancillary data channel and extra forward error correction
  • GSM:
    Audio performance varies with phone circuit conditions
    • Up to 7 kHz on bit rates as low as 9600 kbps with fewer digital artifacts
  • ISDN:
    • MPEG Audio Layer III–15 kHz mono over a single ISDN "B" channel
    • G.722–7.5 kHz mono, low delay, over a single ISDN "B" channel
    • Comrex Turbo G.722–15 kHz mono, low delay, over 2 ISDN "B" channels
  • TelCell:
    • Standard POTS response of 300 Hz–3 kHz

Coding Delay

Delay specified does not include transmission delay

  • POTS: 100 ms
  • GSM: 120 ms (Note: GSM transmission delay may be significant)
  • ISDN
    • G.722 and Turbo G.722: 6 ms
    • MPEG Audio Layer III: 310 ms
  • TelCell: Matrix Portable contributes no delay

Power and physical

  • External power supply: 24 V for 120/240 VAC 60/50 Hz operation
  • Size: 9.5" W x 10" D x 3.5" H (24.1 cm x 25.4 cm x 8.9 cm)
  • Weight: 2.5 lbs (1.1 kg)

Matrix Portable ISDN Module

Connections

  • ISDN line connection: RJ-45
  • External DCE port: DB-9 pin connector allows bypass of the internal terminal adapter to connect to an external terminal adapter, DSU, satellite terminal, etc.

Levels

  • Ancillary data: RS-232
  • DCE in/out: RS-422

Physical

  • Powered through Matrix Portable
  • Size: 4.25" W x 6.5" D x 1.5" H (10.8 cm x 16.5 cm x 3.8 cm)
  • Net weight: 0.68 lbs (0.31 kg)

Matrix Portable GSM Module

Physical

  • Powered through Matrix Portable
  • Size: 4.25" W x 6.5" D X 1.5" H (10.8 cm x 16.5 cm x 3.8 cm)
  • Net weight: 0.72 lbs (0.32 kg)
  • Antenna
    • Height with base: 3"
    • Connector: SM

Matrix Portable TelCell Module

Connections

  • Hands-Free Cell: 1/8" 3-conductor mini-jack
  • Tel Line: RJ11 6-pin modular jack

Physical

  • Powered through Matrix Portable
  • Size: 4.25" W x 6.5" D X 1.5" H (10.8 cm x 16.5 cm x 3.8 cm)
  • Net weight: 0.52 lbs (0.23 kg)

 

 

Matrix Rack Specifications

All specifications are subject to change

Audio connections

  • Balanced XLR line-level audio input—adjustable level
  • Balanced XLR line-level audio output—adjustable level

Other connections

  • Telephone line and telephone set: RJ-11 6-pin modular jacks (2)
  • Contact closures: 2-conductor mini-jacks (4)
    • One latching output, enabled upon the decoder synching with far-end codec
    • One momentary output, activated by a button press on the far-end codec
    • One momentary input that activates a corresponding contact closure output on the far-end codec (performs same function as front-panel “CC” button)
    • One momentary input that initiates dialing of a preselected, stored telephone number. May be used for applications such as backup studio-transmitter-link
  • Auxiliary data port: DB-9
  • Power: 3 conductor IEC

Audio levels

  • Audio input level: selectable -10, 0 and +4 dBu @ 20 KΩ (via jumper to +8 dBu)
  • Audio output level: selectable -10, 0 and +4 dBu @ 100Ω (via jumper to +8 dBu)

Audio Performance

  • POTS:
    Audio performance varies with phone circuit conditions
    • Full duplex FM quality (15 kHz) audio bandwidth at connect rates of 24 kbps and above
    • Full duplex audio scales from 12 kHz to 5 kHz at connect rates of 21.6 kbps to 9.6 kbps
    • Selectable “Voice Mode” allows 7 kHz audio with a 300 bps ancillary data channel and extra forward error correction
  • GSM:
    Audio performance varies with phone circuit conditions
    • Up to 7 kHz on bit rates as low as 9600 kbps with fewer digital artifacts
  • ISDN:
    • MPEG Audio Layer III–15 kHz mono over a single ISDN "B" channel
    • G.722–7.5 kHz mono, low delay, over a single ISDN "B" channel
    • Comrex Turbo G.722–15 kHz mono, low delay, over two ISDN ""B" channels

Coding Delay

Delay specified does not include transmission delay

  • POTS: 100 ms
  • GSM: 120 ms (Note: GSM transmission delay may be significant)
  • ISDN
    • G.722 and Turbo G.722: 6 ms
    • MPEG Audio Layer III: 310 m

Power and physical

  • Internal supply: 120/240 VAC 60/50 Hz
  • Size: 1U Rack 19" W x 8" D x 1.75" H (48.25 cm x 20.3 cm x 4.5 cm)
  • Weight: 5.5 lbs (2.5 kg)

Matrix Rack ISDN Module

Connections

  • ISDN line connection: RJ-45
  • External DCE port: DB-9 pin connector allows bypass of the internal terminal adapter to connect to an external terminal adapter, DSU, satellite terminal, etc.

Levels

  • Ancillary data: RS-232
  • DCE in/out: RS-422

Physical

  • Powered through Matrix Rack
  • Size: 3.5" W x 7.5" D x .75" H (8.9 cm x 19 cm x 1.9 cm)
  • Net weight: 0.4 lbs (0.2 kg)