Convex 2241A Operating Manual

2241A AUDIO / PTT DISTRIBUTION PANEL

Issue Date: December 2004

(C) Copyright 2004 CONVEX CORPORATION

OPERATING MANUAL

www.ConvexCorp.com

2241A Distribution Panel CONTENTS

SECTION 1 GENERAL
PAGE

1-1 INTRODUCTION.....................1-1

1-2 MOUNTING.........................1-1

1-3 POWER............................1-1

1-4 POWER ALARM / INDICATORS.........1-1

1-5 AUDIO AND PTT DISTRIBUTION.......1-1

1-6 PTT BUFFERING....................1-2

1-7 PTT CONVERSION...................1-2

1-8 KEY DETECT.......................1-2

1-9 PTT DISTRIBUTION.................1-2

1-10 PTT OUTPUT CIRCUIT...............1-2

1-11 AUDIO INPUT CIRCUITS.............1-2

1-12 AUDIO INPUT / SUM CIRCUITS.......1-2

1-13 AUDIO OUTPUT CIRCUITS............1-2

1-14 SPECIFICATIONS...................1-3

SECTION 2 INSTALLATION

2-1 INTRODUCTION.....................2-1

2-2 RECEIVING INSPECTION.............2-1

2-3 RECEIVING OPERATIONAL CHECK......2-1

2-3-1 OPERATIONAL CHECK / AUDIO........2-1

2-3-2 OPERATIONAL CHECK / PTT..........2-3

2-3-3 OPERATIONAL CHECK / ALARM LOGIC..2-3

2-4 POWER MODULE REPLACEMENT.........2-4

2-5 INSTALLATION.....................2-4

2-5-1 SWITCH CONFIGURATION.............2-4

2-5-2 MOUNTING.........................2-5

2-5-3 SIGNAL AND POWER CONNECTIONS.....2-6

2-5-4 SYSTEM TESTING...................2-6

2-6 SUPPORT..........................2-6

2-7 WARRANTY.........................2-6

2-8 PRODUCT REPAIR SERVICE...........2-6

SECTION 3 OPERATION

3-1 INTRODUCTION.....................3-1

3-2 AUDIO DISTRIBUTION...............3-1

3-3 AUDIO GAIN CONTROLS..............3-1

3-4 PTT DISTRIBUTION.................3-1

3-5 FRONT PANEL / PTT CONTROLS.......3-1

3-1-1 INSTALLATION AND MAINTENANCE.....3-2

3-5-2 TROUBLE SHOOTING.................3-2

3-5-3 SPECIAL CASES / ADAPTATION.......3-2

FINAL NOTE.......................3-2

ADVERTISEMENT....................3-2

SECTION 1 ILLUSTRATIONS
PAGE

FRONT / REAR PANEL.....................1-1

2241A APPLICATION......................1-1

BLOCK DIAGRAM 2241A AUDIO / PTT........1-1

BLOCK DIAGRAM PTT CIRCUIT..............1-1

BLOCK DIAGRAM PTT CIRCUIT..............1-2

BLOCK DIAGRAM 2241A AUDIO / PTT........1-3

SECTION 2 ILLUSTRATIONS

FRONT / REAR PANEL................. ...2-1

BLOCK DIAGRAM 2241A AUDIO / PTT........2-2

2241A SWITCH LOCATION DRAWING..........2-2

FRONT / REAR PANEL.....................2-3

FRONT / REAR PANEL.....................2-5

BLOCK DIAGRAM 2241A AUDIO / PTT........2-5

2241A APPLICATION......................2-6

SECTION 3 ILLUSTRATIONS

FRONT / REAR PANEL.....................3-1

2241A APPLICATION......................3-1

BLOCK DIAGRAM 2241A AUDIO / PTT........3-1

BLOCK DIAGRAM PTT CIRCUIT..............3-1

FEDERAL COMMUNICATIONS COMMISSION (FCC) REGULATIONS

This equipment is certified to comply with the limits for a Class A computing devices, pursuant to
Part 15, Subpart J of the FCC Rules. These limits are designed to provide reasonable protection
against harmful interference when the equipment is operated in a commercial environment.

C -1

2241A Distribution Panel GENERAL Section 1

FRONT VIEW

CONVEX 2241A AUDIO / PTT DISTRIBUTION PANEL

KEY
NORMAL
DISABLE

PTT

90-264 VAC

1/2 AMP

BACKUPMAIN

PTT

FUSE FUSE

1-1 INTRODUCTION The Convex 2241A AUDIO /
PTT DISTRIBUTION PANEL is used to manage “Talk

Out” Audio and Push to Talk (PTT) signals bound for
local or remote radios. It provides a compact means of
distributing audio and Push to Talk (PTT) signals to as
many as 24 base stations. In addition, it provides
manual PTT override for individual transmitters. 24 front
panel switches permit each radio to be keyed, disabled,
or to track normal console control. Manual PTT control
is used for installation and management of radio
networks. It is also used to align simulcast networks by
enabling one transmitter at a time to perform delay
measurements.

LOCAL RADIOSTO REMOTE RADIOS

Tx AUDIO

T1 MUX

M LEAD / PTT

PTT PTTTx Tx

UP TO 24 PTT OUTPUTSUP TO 24 Tx OUTPUTS

2241A AUDIO / PTT DISTRIBUTION PANEL

PTT NORM

1713 14 15 16 18 19 20 21 22 23 24121110987654321

UP TO 8 SUM INPUTSUP TO 8 Tx INPUTS

Tx AUDIO

Rx AUDIO

M LEAD / PTT

DISPATCH CONSOLE

CONVEX 2241A AUDIO / PTT DISTRIBUTION PANEL

UP TO 24 PTT INPUTS

KEY
DISABLE

VOTER

POWER

BUMAIN

1-2 MOUNTING The 2241A is packaged in a 1U high,
rack mounting, panel. It is 12 Inches deep, and mounts
in a 19 Inch Rack or Equipment Cabinet. At 1.7 Inches
high, it takes up only one unit of vertical space.

1-3 POWER Power options include a universal AC
Supply; or 12, 24, or 48 Volt DC Supplies. All power

supply options include redundant, replaceable power
modules. The MAIN and BACKUP Power Modules are
fused independently. In the event of a failure, a power
module can be replaced with out taking the panel out of
service. Section 2 has the procedure for replacing a
failed power module while the 2241A is in service.

1-4 POWER ALARM / INDICATORS Front panel
LEDs indicate the status of each power module. A
contact closure is provided across pins 25/50 on the
Audio Output Connector to alarm in the event of a
power module failure.

1713 14 15 16 18 19 20 21 22 23 24121110987654321

REAR VIEW

CONVEX

2241A AUDIO / PTT DISTRIBUTION PANEL

AUDIOOUTPUTOUTPUT INPUTINPUT

S/N

MADE IN USA

1-5 AUDIO and PTT DISTRIBUTION Distribution is
configured by 7 internal switches which can be set to fan
out a single input to up to 24 outputs, 2 inputs to 12
outputs, or various other configurations. The distribution
switches simultaneously configure both Audio and PTT
Signals.

Distribution Capacity: 24 Audio Outputs per 2241A

8 Audio Inputs per 2241A
8 Summing Audio Inputs
24 PTT Outputs per 2241A
8 PTT Inputs can be distributed
( 24 PTT Inputs for buffering or

PTT Logic conversion )

PTT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PUSH TO TALK CIRCUITS

KEY
NORM
DISABLE

HI Z

S10

600

HI Z

S11

600

HI Z

S12

600

HI Z

S13

600

HI Z

S14

600

HI Z

S15

600

HI Z

S16

600

HI Z

S17

600

10K

INPUT
LOGIC

+12 +12+5 +5E/M

(STATION BATTERY)

AUDIO

B1

S1A

IN4

B2

S2A

IN7

B3

S3A

IN10

B4

S4A

IN13

B5

S5A

IN16

B6

S6A

IN19

B7

S7A

IN22

KEY

DETECT

1/26
2/27 2

4

4/29
5/30 5

7

7/32

8

8/33

10

10/35

11

11/36

13

13/38

14

14/39

1616/41
1717/42

1919/44
2020/45

22

22/47

23

23/48

600 OHM, BALANCED RECEIVERS / DRIVERS

DET GND
25,50

1-24
PTT IN

26-49

-48/SB

BUS 1

PINSOUTPUTINPUTPINS

1
2
3

4
5
6

7
8
9

10

10/35

11

11/36

12

12/37

13

13/38

14

14/39

15

15/40

16

16/41

17

17/42

18

18/43

19

19/44

20

20/45

21

21/46

22

22/47

23

23/48

24

24/49

1 1

1/261

2 2

2/27

3 3

3/28

4/29
5/30
6/31

7/32
8/33
9/34

S1B

4 4
5 5
6 6

S2B

7 7
8 8
9 9

S3B

10 10
11 11
12 12

S4B

13 13
14 14
15 15

S5B

16 16
17 17
18 18

S6B

19 19
20 20
21 21

S7B

22 22
23 23
24 24

BLOCK DIAGRAM / 2241A AUDIO / PTT DISTRIBUTION PANEL

S90-S113

S42-S65

TTL

DIG

DIST IN

E/M SEL
M:I,II,III

M:IV,V,E
(INVERT)

ON

S8,S9

OFF

DIST OUT

BLOCK DIAGRAM / PTT CIRCUIT

S18-S41

PTT
CONTROL

RED

RED

(FRONT PANEL)

*Digitac is a Trademark of Motorola Inc.

POWER SUPPLY

BACKUP

MAIN

OUTPUT / PINSPINS / INPUT

PTT

OUTPUT
LOGIC

E/M

TTL

PTT OUT

10K

S66-S89

DET GND

DIG

GND/SG

1-24

25,50

26-49

1 - 1

2241A Distribution Panel GENERAL Section 1

1-6 PTT BUFFERING. High current PTT Outputs

permit direct drive of transmitters requiring up to 100
mA keying current. The Panel accepts 12 or 24 low
current PTT Inputs and provides high current outputs.
Two switches permit the PTT Circuits to be configured
for Distribution or Buffering (Distribution OFF). The first
switch controls PTT Outputs 1-12, the second controls
PTT Outputs 13 -24. This arrangement permits a
combination of both Distributed and Buffered PTT
Circuits. That is, 12 Outputs can be set for Distribution
and 12 PTT Circuits can be set to Buffer Mode. In either

mode, the front panel PTT Controls are operational.

M:I,II,III

M:IV,V,E

(INVERT)

DIST IN

DIST OUT

ON

PTT

S3

CONTROL

OFF

RED

S4

(FRONT PANEL)

KEY
NORM

OFF/GRN

RED

DISABLE

PTT OUT

1-24

DET GND

PTT

OUTPUT
LOGIC

25,50

S5

E/M

TTL

DIG

26-49

GND/SG

26-49

-48/SB

DET GND
25,50

1-24
PTT IN

INPUT
LOGIC

+12 +12+5 +5E/M

DETECT

KEY

TTL

E/M SEL

S2

S1

DIG

BLOCK DIAGRAM / PTT CIRCUIT

1-7 PTT CONVERSION. Each PTT Circuit has two
independent PTT Logic Switches which select among:
E/M, TTL, and Digitac Logic types. One switch (INPUT)
configures the PTT Detector, and the other configures
the PTT Output. PTT Logic conversion is simply a
matter of selecting the desired Input and Output Logic
Types.

1-8 KEY DETECT. Two switches permit each Key
Detector to be set to accept a wide variety of PTT Logic
Types. The INPUT LOGIC Switch selects among: E/M,
TTL, and Digitac Logic types. The E/M SELECTOR
provides a choice of E/M Type, or it is used to invert
TTL or Digitac PTT Logic - when needed.

INPUT LOGIC Switch. This three position switch
selects among: E/M, TTL, and Digitac Logic types by
setting the detector trip voltage and the voltage on the
pull-up resistor. The purpose of the pull-up resistor is to
force an idle condition if the PTT Input circuit is open or
not asserted.

E/M SELECTOR Switch. This two position switch
selects the E/M Type or an INVERT function. Position 1
is used for Type: I, II, or III M Lead Inputs. In this
position the “pull-up” resistor is connected to the
detector ground and PTT is asserted when the Input is
less than ( more negative ) -20 Volts. Position 2 is used
for E Leads or Type IV or V M Lead Inputs. In this
position the “pull-up” resistor is connected to “SB”
Signal Battery / -48 Volt Input Lead and PTT is asserted
when the Input is greater than ( more positive ) -20
Volts. Position 2 is also used to INVERT TTL or
Digitac Logic when needed. In this case, PTT is
asserted when INPUT Lead is open or high.

1-9 PTT DISTRIBUTION. The 2241A can be set so that
individual PTT Inputs can be distributed to multiple PTT
Outputs. Two DISTRIBUTION switches control this
function. The first switch controls PTT Outputs 1-12, and
the second switch controls PTT Outputs 13-24. When
the DISTRIBUTION Switch is ON, multiple PTT

Outputs will track the state of an individual PTT Input. In
this case, the PTT distribution fan-out tracks the audio
distribution fan-out which is determined by the state of
seven, Audio Distribution Switches. For example, if
Audio Input 1 is set for distribution to Audio Outputs 1-6,
then PTT Input 1 will be distributed to PTT Outputs 1-6.
When the DISTRIBUTION Switch is OFF, each PTT
Outputs will track the state of its individual PTT Input.

1-10 PTT OUTPUT Circuit. Each PTT Output circuit
provides a contact closure when PTT is asserted
(transmitter keyed). There is an independent, three
position, PTT Logic Switch for each PTT Output
Circuit. This switch which selects among: E/M, TTL, and
Digitac Logic types and selects the voltage for the pull­up resistor.

PTT OVERRIDE Switch. Each PTT Output Circuit has
a PTT Override Switch located on the front panel of the
2241A. The PTT Override Switch permits manual
control of PTT to facilitate installation, trouble shooting,
or temporary reconfiguration of a radio system. This is a
three position, lighted, toggle switch with the center
position being the NORMAL setting. In the Normal
Position, the PTT Output tracks the PTT Input and the
switch bat lights up GREEN when PTT is asserted. In
the KEY (UP) Position, the switch bat lights up RED and
the PTT Output is asserted, regardless of the state of
the PTT Input. In the DISABLE (DOWN) Position, the
switch bat lights up RED and the PTT Output is
disabled, regardless of the state of the PTT Input.

1-11 AUDIO INPUT Circuits. Eight Audio Input Circuits
are provided. These circuits are balanced and floating
with a fixed 600 Ohm Input Impedance. They can be
driven from a balanced or single ended source.

1-12 AUDIO INPUT / SUM Circuits. Eight Audio Input
Sum Circuits are provided. These circuits are primarily
used to sum (voted) receiver audio with transmit audio.
They are balanced and floating and have an Input
Impedance Switch. This switch is set to HI Z ( 20 K
Ohms) when the sum input is paralleled with (bridging)
another 600 Ohm Input. It is set to 600 Ohms when the
sum input is used to terminate a circuit, or when the

Sum Input is not in use.

1-13 AUDIO OUTPUT Circuits. There are 24 Audio
Output Circuits. These circuits are balanced and floating
with a fixed 600 Ohm Output Impedance. They can be
terminated with a balanced or single ended load. The
(Input to Output) gain of the audio circuits is factory set
to unity / 0.0 dB. However, a front panel, screw
adjustment, GAIN CONTROL is provided for
normalizing transmitter deviation. This control has a
range of +/- 10 dB (0.316 to 3.16) with a logarithmic
characteristic that provides a constant dB gain change
per degree of rotation. Use of 15 turn potentiometers
provides high resolution control.

* Digitac is a Trademark of Motorola Inc.

1 - 2

2241A Distribution Panel GENERAL Section 1

1-14 SPECIFICATIONS

AUDIO DISTRIBUTION AMPS

Frequency Range: 20 Hz to 5000 Hz
Tx Inputs: 8 Floating, Balanced, 600 Ohm
Sum Inputs 8 Floating, Balanced, 600 / Hi Z
Outputs: 24 Floating, Balanced, 600
Ohm
Gain: 0 dB, +/- 10 dB / 24 FP controls
I/O Return Loss: Greater than 26 dB
Input/Output Level: +10 dBm maximum
Noise: Less than -60 dBmC

PTT CIRCUITS

Outputs: 24 High Current (100 mA) Outputs

E/M, TTL, or *Digitac / Relay Closure

Inputs: 24 E/M Type 1-5, TTL, or *Digitac

8 Inputs for distribution applications
M Type I,II,III: Key <-20 V / Idle >-20

V

M Type IV, V; E: Key >-20 / Idle <-20 V
TTL: Key < +2.5 V / Idle > +2.5 V
*Digitac: Key < +6 V / Idle > +6 V

* Digitac is a Trademark of Motorola Inc.

AUDIO / PTT DISTRIBUTION CONTROL

7 Switches: 1 Input to 24 Outputs, or

2 Inputs to 12 Outputs each, or
numerous other distribution options.

MANUAL PTT CONTROL

PTT Switches 24 (3 Position) Front Panel Switches

KEY: Keys transmitter / Lit Red
NORMAL Console control / Lit Green =

PTT

DISABLE Disables PTT / Lit Red

HI Z

S10

600

HI Z

S11

600

HI Z

S12

600

HI Z

S13

600

HI Z

S14

600

HI Z

S15

600

HI Z

S16

600

HI Z

S17

600

10K

INPUT
LOGIC

+12 +12+5 +5E/M

(STATION BATTERY)

AUDIO

B1

S1A

IN4

B2

S2A

IN7

B3

S3A

IN10

B4

S4A

IN13

B5

S5A

IN16

B6

S6A

IN19

B7

S7A

IN22

KEY

DETECT

1/26
2/27 2

4

4/29
5/30 5

7

7/32

8

8/33

10

10/35

11

11/36

13

13/38

14

14/39

1616/41
1717/42

1919/44
2020/45

22

22/47

23

23/48

600 OHM, BALANCED RECEIVERS / DRIVERS

DET GND
25,50

1-24
PTT IN

26-49

-48/SB

BUS 1

PINSOUTPUTINPUTPINS

1
2
3

4
5
6

7
8
9

10

10/35

11

11/36

12

12/37

13

13/38

14

14/39

15

15/40

16

16/41

17

17/42

18

18/43

19

19/44

20

20/45

21

21/46

22

22/47

23

23/48

24

24/49

1 1

1/261

2 2

2/27

3 3

3/28

4/29
5/30
6/31

7/32
8/33

9/34

S1B

4 4
5 5
6 6

S2B

7 7
8 8

9 9

S3B

10 10
11 11
12 12

S4B

13 13
14 14
15 15

S5B

16 16
17 17
18 18

S6B

19 19
20 20
21 21

S7B

22 22
23 23
24 24

PUSH TO TALK CIRCUITS

BLOCK DIAGRAM / 2241A AUDIO / PTT DISTRIBUTION PANEL

S90-S113

S42-S65

TTL

DIG

DIST IN

E/M SEL
M:I,II,III

M:IV,V,E
(INVERT)

ON

S8,S9

OFF

DIST OUT

BLOCK DIAGRAM / PTT CIRCUIT

S18-S41

PTT
CONTROL

RED

RED

(FRONT PANEL)

KEY
NORM
DISABLE

PTT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT

OUTPUT
LOGIC

OUTPUT / PINSPINS / INPUT

PTT OUT

1-24

DET GND

25,50

10K

S66-S89

E/M

TTL

DIG

26-49

GND/SG

ENVIRONMENT: -30 to 60º C, 95% R.H.
I/O CONNECTORS: 2 sets of 50 pin "Telco" type
DIMENSIONS: 1.7" H x 12" D x 19" W. / 6 lbs.
POWER 90-264 VAC; Order: 2241A-AC

12, 24, or 48 VDC, Order: 2241A-XX

1 - 3

2241A Distribution Panel INSTALLATION Section 2

FRONT VIEW

CONVEX 2241A AUDIO / PTT DISTRIBUTION PANEL

KEY
NORMAL
DISABLE

PTT

90-264 VAC

1/2 AMP

BACKUPMAIN

PTT

FUSE FUSE

2-1 INTRODUCTION This section is organized into four
parts dealing with: Receiving Inspection, Power Module
Replacement, Installation, Support and Service.
Receiving Inspection consists of a visual examination
and brief operational checks to verify that the 2241A has
not been damaged in transit. Power Module
Replacement provides a procedure to replace a power
module with the 2241A in service. Installation discuses
mounting, I/O and power hook-up, and configuration.
Support and Service includes factory assistance with
applications, operation and repairs.

2-2 RECEIVING INSPECTION Prior to shipment each
2241A is tested electrically and inspected for good
mechanical condition. New units should be free of
mechanical defects and new (or repaired) units should
be in good operating order. Inspect the equipment on
receipt to insure that it has not been damaged in transit.
If damage is observed, retain the shipping carton and its
contents and file a claim with the freight carrier.

2-3 RECEIVING OPERATIONAL CHECK Look at the
rear panel to determine the appropriate power voltage.

AC Units have a North American Type power cord
attached. If needed - replace the plug on the power cord
with one intended for the local power mains. The AC
mains voltage must be in the range of 90 to 264 Volts
rms. If so, then plug into the power receptacle to power
the unit. (The 2241A does not have a power switch.)

DC Units have a power terminal block on the left side of
the rear panel. Check the label over the terminal block
to determine the correct supply voltage and current
requirements. Standard voltages are 12, 24, or 48 VDC.
Prior to connecting the DC Power Supply, check that its
voltage is within +/- 2 volts of the labeled voltage, and
that it will provide the current listed near the Fuses.

Turn the DC Power Supply OFF, and connect 2 heavy
gage wires between the power supply and the + and -
terminals on the 2241A - observing the polarity labels.
As a safety precaution, connect a heavy gauge wire
between the Earth (Chassis) Ground and the Earth /
Safety Ground. Then turn on the DC Power Supply to
activate the 2241A.
Check the front panel of the 2241A and observe that
both MAIN and BACKUP LEDs are lit. If one of the
LEDs is not lit, place an OHM Meter across AUDIO OUT
Connector (ALARM) pins 25 and 50. If a power supply

1713 14 15 16 18 19 20 21 22 23 24121110987654321

REAR VIEW

CONVEX

2241A AUDIO / PTT DISTRIBUTION PANEL

AUDIOOUTPUTOUTPUT INPUTINPUT

POWER SUPPLY
MAIN

S/N

MADE IN USA

has failed there will be a low OHM reading (<100
Ohms). If there is a high OHM reading, then both
power supplies may be working, but there has been
another failure such as a defective LED. In this case
contact Convex to arrange for return for warranty repair.

If there is a low OHM reading, then one of the power
supplies is not operating. In this case, remove power
and check the fuse (on the rear of the 2241A) which
corresponds with an unlit LED. Replace any missing or
blown fuses, then reapply power and verify that both
LEDs are lit. If an LED remains unlit after replacing a
fuse, contact Convex for return for repair.

2-3-1 OPERATIONAL CHECK / AUDIO CIRCUITRY

The audio circuitry has been tested prior to shipment
and will not generally need to be rechecked prior to
installation. This procedure is provided so that the
checks can be made when needed. The audio checks
are made using a Convex 806A TIMS Test Set or
equivalent equipment. Audio checks assume that the

seven Distribution Switches (S1-S7) and Gain Controls
are set to the factory default settings: Input / 0 dB.

Set the 806A Generator for 1004 Hz / 0 dBm / 600 Ohm
Send Impedance. Set the 806A Receiver for LEVEL
Mode / 15 kHz Filter / 600 Ohm Termination.

Audio Check. Drive pins 1/26 of the Audio Input
Connector with the 806A Generator, and use the 806A
Receiver to verify 0 dBm (+/- 0.5 dB) / 1004 Hz on pins
1/26, 2/27, and 3/28 of the Audio Output Connector.

Repeat the above Audio Check driving pins 2/27
Repeat the above Audio Check for pins 4/29 of the

Audio Input Connector and pins 4/29, 5/30, 6/31 of the
Audio Output Connector.

Repeat the above Audio Check driving pins 5/30
Repeat the above Audio Check for pins 7/32 of the

Audio Input Connector and pins 7/32, 8/33, 9/34 of the
Audio Output Connector.

Repeat the above Audio Check driving pins 8/33
Repeat the above Audio Check for pins 10/35 of the

Audio Input Connector and pins 10/35, 11/36, 12/37 of
the Audio Output Connector.

Repeat the above Audio Check driving pins 11/36

2 - 1

BACKUP

2241A Distribution Panel INSTALLATION Section 2

1/26
2/27 2

4/29
5/30 5

7/32
8/33

10/35
11/36

13/38
14/39

10
11

13
14

1616/41
1717/42

1919/44
2020/45

22/47

22

AUDIO

BUS 1

B1

HI Z

600

S1A

S10

IN4

4

B2

HI Z

600

S2A

S11

IN7

7
8

HI Z

600

HI Z

600

HI Z

600

HI Z

600

HI Z

600

B3

S3A

S12

IN10

B4

S13

S4A

IN13

B5

S5A

S14

IN16

B6

S6A

S15

IN19

B7

S7A

S16

IN22

1
2
3

4
5
6

7
8
9

10
11
12

13
14
15

16
17
18

19
20
21

22

PINSOUTPUTINPUTPINS

1/261
2/27
3/28

4/29
5/30
6/31

7/32
8/33

9/34

10/35
11/36
12/37

13/38
14/39
15/40

16/41
17/42
18/43

19/44
20/45
21/46

22/47

1 1
2 2
3 3

S1B

4 4
5 5
6 6

S2B

7 7
8 8

9 9

10 10

S3B

11 11
12 12

13 13

S4B

14 14
15 15

16 16

S5B

17 17
18 18

19 19

S6B

20 20
21 21

22 22

S7B

PTT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

OUTPUT / PINSPINS / INPUT

23/48

23

HI Z

S17

600

600 OHM, BALANCED RECEIVERS / DRIVERS

BLOCK DIAGRAM / 2241A AUDIO / PTT DISTRIBUTION PANEL

DET GND
25,50

1-24
PTT IN

26-49

-48/SB

10K

INPUT
LOGIC

+12 +12+5 +5E/M

(STATION BATTERY)

KEY

DETECT

S42-S65

TTL

DIG

S90-S113

23

23/48

24

24/49

E/M SEL
M:I,II,III

M:IV,V,E

(INVERT)

DIST IN

ON

S8,S9

OFF

DIST OUT

S18-S41

BLOCK DIAGRAM / PTT CIRCUIT

2 - 2

23 23
24 24

PTT CIRCUIT

PTT CIRCUIT

PUSH TO TALK CIRCUITS

PTT OUT

TTL

DET GND

10K

S66-S89

DIG

GND/SG

1-24

25,50

26-49

PTT
CONTROL

RED

RED

(FRONT PANEL)

KEY
NORM

DISABLE

PTT

OUTPUT
LOGIC

E/M

2241A Distribution Panel INSTALLATION Section 2

2 - 2

Z1

R20

R518

J1 J2

R651

R647

S68 S69

S56

S111 S112

C132

Q16

Q12

Q11

Q17

Z62

D9

D15

D11

D14
D13D10

R502 R512

RN11

RN12

R510

Z41

R520

K2

R503 R513

R501

Z99

R511

R504 R514
R505 R515

R507 R517

R506

R657

R644

R317

R319

R318

R617

R322
R324

R323

D52

R607

Q64

Q65

Q63

R320

RN39

Z109

C142

R134

R17 R18 R19

Z2

RN45

R618

RN4

R609

R608

Z37

R123

C81

R146

R499

R124

R122

R305

R121

R133

R132

C106

C60

C59

R327
R328

J3

RN37

R350

Z50

R329

R516

C33

C34

R70

R73

R68

R340

C18

C112

C111

Q73

R345

R336

R145

Q75

R337
R339

R316

R338

Z27

Z110

Q74

D60

R353

R354

R352

R348

R349

R347

C141

R150

R141

Z108

Z25

Q79

Q78

Q80

Z76

D64

C143

Z28

RN44

D98

R351

R360

R355

C62

R67

C61

R342

R72

R74

R11

R79

R343

R10

C20

R331

R71

R9

R332

R69

R334

C17

R639

C19

R356

C109

R333

S7

Z51

R344

S35S34

Z77

R371
R370

R346

R359

Z52

R66

RN43

R358

R65

C24

C23

C21

R12

C22

R357

C116

R77

C63

C64

C110

R76

S63

R75

R80

R78

Z7

R32

R698

S86 S87

S46

R335

S91

RN10

S96

S47

S70 S71

S64

S109 S110

RN2

Q26

Q22

Q21

Q27

Z14

D8

Z63

D17

Q10

Q8

Q9

D23

D19

D22
D21D18

R522

R194

C150

R532

RN17

RN18

R530 R540

K3

R523

Q106

R533

R521

Q102

R531

Q101

R527

Q107

R537

Z71

R524

D81

D87

D83

D86
D85D82

R682 R692

RN65

RN66

R690

Z59

R700

K11

R683 R693

R681

Z117

R691

R684 R694
R685 R695

R687

R137

R697

R686

R404

R29 R30 R31

Z8

RN58

Z55

R393

R139

R138

C117

R416

R679

R394

R392
R391

R403

R402

R696

C69

C70

R415

R420

R411

Z85

R654

Z86

RN64

S65

S88 S89

S62

S113

S6

RN56

Q116

Q112

Q111

Q117

Z32

D80

Z72

D89

Q100

Q98

Q99

D95

D91

D94
D93D90

R702

R464

R712

RN71

RN72

R710 R720

K12

R703 R713

R701 R711

R707 R717

R704

R407

R409

R408

R677

R412
R414

R413

D76

R667

Q94

Q95

Q93

R410

RN57

Z115

C148

RN63

R678

R669

R668

R395

C115

C118

C72

C71

R417
R418

RN55

R440

Z56

R419

R86

R89

S5

R84

R375

R430

R366

R367

C26

C124

C123

Q103

R369
R368

Z29

Z112

C145

J5

R376

R389

R308

R309

R307

Z54

RN49

R388

R306

R315

R387

C107

C67

C68

C114

R435

R365

R426

Q105

R427

R648

R649

R658

R111

C146

R110

Z113

R112

R497

RN51

R380

R429

C108

R406

R113

R428

Q83

Q85

R645

Z33

Q84

R109

Z116

R114

D68

Q104

S33

R310

D84

R443R383

R444R384

S4

R382

R378

R379

R377

R442

R628

R629

S32

Q89

Q88

Q90

D72

R438

R439

R437

Z30

R142
R144

R143

C147

RN50

Z114

R381

Z31

R390

Q109

R385

C66

D4

Q108

C65

R487

R372
R373

Q110

Q4

Q5

Q3

R140

RN3

D88

Z97

C149C130

RN9

R361

R362

R498

R489

R488

R125

R364

R659

R386

C113

Z34

C82

RN62

R441

R450

R445

C74

R83

C73

R432

R88

R90

C36

C35

R147

R15

R148

R95

R433

R14

C28

R421

R87

R13

R422

RN1

R85

R170

R424

Z38

R149

C25

R699

C27

R446

C121

R423

Z57

R655

R434

S41S40

R461
R460

R436

R449

Z58

R341

R82

R616R606

R615

RN61

R448

R605

R614R604

R611R601

R613

R81

C32

C31

R603

K7

R620R610

RN42

RN41

R612R602

D50 D53

D54

D51

R311

D55

D49

C29

R16

C30

Z67

Q67

R447

C128

Z84

Q61

Q62

Q66

S30

R93

S31

C75

C76

C122

R92

S44

R91

R96

R94

R425

R714

C127

R465

R456

R457
R459

R458

Z35

Z118

C151

S3

R466

R479

R398

R399

R397

Z60

RN67

R478

R396

R405

R477

C119

C79

C80

C126

R455

R708

R709

R718

R117

C152

R116

J4

Z119

R118

K13

RN69

R470

C120

R119

Q113

D97

Q115

R705

Q114

R115

R120

D92

S39

R400

R473

R474

R472

R468

R469

R467

R688

R689

S38

S2

Q118

S1

D96

Z36

R38

RN68

R471

R480

R475

R41

C78

C77

R462
R463

R451

R452

R454

R719

R476

C125

R715

R431

R676R666

R675R665

R674R664

R36

R671

R160

C2

R661

C88

S9

C87

Q13

R165

R156

Q15

R157
R159

R136

R158

Z15

Z98

Q14

D12

R173

R174

R172

R168

R169

R167

R646

C129

Z96

Z13

Q19

RN52

R673R663

K10

Q18

Q20

D16

R680R670

RN60

RN59

R672

C131

Z16

R662

D74 D77

D78

D75

R401

RN8

R171

D79

D73

Z70

Q97

R180

R175

C38

R35

Z87

Q91

Q92

C37

R162

R40

R42

R3

R47

R163

R2

C4

R151

R39

R1

Q96

R152

R37

R154

C1

R519

C3

R176

C85

R153

Z39

R164

S36S23S22

R191
R190

S37

R656

R166

R179

Z40

R34

RN7

R178

R706

RN70

R33

C8

C7

R716

S104 S107

C5

R4

R453

S17

C6

R177

C92

R45

C39

Z94

S99S93

C40

C86

R44

S85

R43

R48

S16

R46

Z12

Z95

S84

S61

R363

S15

Z92

S14

Z11

S79

Z93

S60

S78

S55S54S51

S100

Z3

R24

R578

S74 S75

S52

R155

S97 S102

C138

Q46

Q42

Q41

Q47

Z65

D33

D39

D35

D38
D37D34

R562 R572

RN29

RN30

R570

Z47

R580

K5

R563 R573

R561

Z105

R571

R564 R574
R565 R575

R567 R577

R566

R224

R21

R22

R23

Z4

RN22

Z43

R213

C93

R236

R559

R214

R212
R211

R223

R222

R576

C45

C46

R235

R240

R231

Z79

R534

Z80

RN28

S53

S76 S77

S50

S98 S101

RN20

Q56

Q52

Q51

Q57

Z20

D32

Z66

D41

Q40

Q38

Q39

D47

D43

D46
D45D42

R582

R284

R592

RN35

RN36

R590 R600

K6

R583 R593

R581 R591

R587 R597

R584

R227

R229

R228

R557

R232
R234

R233

D28

R547

Q34

Q35

Q33

R230

RN21

Z103

C136

RN27

R558

R549

R548

R215

C91

C94

C48

C47

R237
R238

RN19

R260

Z44

R239

R54

R57

U4

ASD08-48D12

OR

ASD08-24D12

OR

ASD08-12D12

R52

R195

R250

R186

R187

C10

C100

C99

Q43

R189
R188

Z17

Z100

C133

R196

R209

R128

R129

R127

Z42

RN13

R208

R126

R135

R207

C83

C43

C44

C90

R255

R185

R246

Q45

R247

R528

R529

R538

R99

C134

R98

Z101

R100

RN15

R200

R249

C84

R226

R101

R248

Q23

Q25

R525

Z21

Q24

R97

Z104

R102

D20

Q44

S21

R130

D36

R263R203

R264R204

U5

ASD08-48S5

OR

ASD08-24S5

OR

ASD08-12S5

R202

R198

R199

R197

R262

R508

R509

S20

Q29

Q28

Q30

D24

R258

R259

R257

Z18

C135

RN14

Z102

R201

Z19

R210

Q49

R205

C42

Q48

C41

R192
R193

Q50

D40

C137

R181

R182

R184

R539

R206

C89

Z22

RN26

R261

R270

R265

C50

R51

C49

R252

R56

R58

R7

R63

R253

R6

C12

R241

R55

R5

R242

R53

R244

C9

R579

C11

R266

C97

R243

Z45

R535

R254

S29S28

R281
R280

R256

R269

Z46

R161

R50

R496R486

R495

RN25

R268

R485

R494R484

R491R481

R493

R49

C16

C15

R483

K1

R500R490

RN6

RN5

R492R482

D2 D5

D6

D3

R131

D7

D1

C13R8C14

Z61

Q7

R267

C104

Z78

Q1Q2Q6

S18

R61

S19

C51

C52

C98

R60

S73

R59

R64

R62

R245

R594

C103

R285

R276

R277
R279

R278

Z23

Z106

C139

U6

ASD08-48S5

OR

ASD08-24S5

OR

ASD08-12S5

R286

R299

R218

R219

R217

Z48

RN31

R298

R216

R225

R297

C95

C55

C56

C102

R275

R588

R589

R598

R105

C140

R104

Z107

R106

RN33

R290

C96

R107

Q53

Q55

R585

Q54

R103

R108

D44

S27

R220

R293

R294

R292

R288

R289

R287

Q119

R568

Q120

R569

S26

Q59

Q58

Q60

D48

Z24

RN32

R291

R300

R295

C54

C53

R282
R283

R271

R272

R274

R599

R296

C101

R595

R251

R556R546

R555R545

R554R544

R551R541

R526

RN16

R553R543

K4

R560R550

RN24

RN23

R552R542

D26 D29

D30

D27

R221

D31

D25

Z64

Q37

Z81

Q31

Q32

Q36

S24 S25

R536 R586

RN34

R596

C153

S92 S95

C156

R273

S13

Z120

Z90

S108S103

U2

C155

S12

Z10

Z91

C154

S72

U1

S49

R183

S11

Z88

Z73

Z74

R721

RN73

R726

R727

R722

R728

R723

R724

R729

R732

R730

R733

R731

Q122

Q121

Q123

R725

C157

S10

Z9

S67

Z89

S48

D99

D100

D102

D103

D104

U3

ASD08-48D12

OR

ASD08-24D12

OR

ASD08-12D12

D101

Z75

S45

S66

S43S42

S83

R641

R653R643

K9

R660R650

RN54

RN53

R652

R374

R642

D66 D69

D70

D67

D71

Q69

Q68

Q70

D65

Z69

D56

Z26

Q87

Q81

Q82

Q86

RN38

S90 S106

S82

S59S58

S81

RN46

Z83

S105

Z82

R321

R330

R325

C58

C57

R636

R312
R313

R301

R302

R304

R619

R326

C105

R303

Z49

RN40

Z6

R27R26R25

R314

R626

R637R627

R635R625

R634R624

R631

Z111

R621

R633R623

K8

R640

Z53

R630

RN48

RN47

R632R622

D58 D61

D62

D59

D63

D57

Z68

Q77

Q71

Q72

Q76

C144

S8

S80

S57

S94

R638

R28

Z5

552725-1 STANDARD RECEPTACLE

50

1

552726-3 REVERSE PLUG

50

1

2907

B

E
C

2907

B

E
C

2907

B

E
C

2907

B

E
C

4454

4454
4454

4454
44544454

4454

2222BE

C

2222BE

C

2222

BEC

10

10

552725-1 STANDARD RECEPTACLE

50

1

10

10

10

2222

BEC

2222BE

C

2222BE

C

4454

2222BE

C

2222

BEC

2222BE

C

4454

10

10

1010

10

10

10

10 10

10

10

2907

B

E
C

2907

B

E
C

2907

B

E
C

2907

B

E
C

4454

4454

2222BE

C

2222

BEC

2222BE

C

4454
4454

4454
44544454

2907

B

E
C

2907

B

E
C

2907

B

E
C

2907

B

E
C

4454

4454
4454

4454
44544454

10

10

2907

B

E
C

2907

B

E
C

2907

B

E
C

2907

B

E
C

4454

4454

2222BE

C

2222

BEC

2222BE

C

4454
4454

4454
44544454

4454

2222BE

C

2222BE

C

2222

BEC

10

10

10

2222

BEC

10

10

2222BE

C

2222

BEC

2222BE

C

2222BE

C

4454

2222BE

C

4454

2222BE

C

2222

BEC

2222BE

C

4454

2222BE

C

10

4454

2222

BEC

10

2222BE

C

2222BE

C

2222BE

C

2222

BEC

4454

10

10

10

10

1010

10

10

10

4454 4454

4454

4454

4454

4454

10 10

2907

B

E
C

2907

B

E
C

2907

B

E
C

2907

B

E
C

10

10

10

10

552726-3 REVERSE PLUG

50

1

2222

BEC

2222BE

C

2222BE

C

4454

2222

BEC

4454

10

10

10

2222

BEC

2222BE

C

2222BE

C

4454

2222BE

C

2222

BEC

2222BE

C

4454

4454 4454

4454

4454

4454

4454

2907

B

E
C

10

2907

B

E
C

2907

B

E
C

10

10

2907

B

E
C

10

10

10

10

10 10

10

10

2907

B

E
C

2907

B

E
C

2907

B

E
C

2907

B

E
C

4454

4454
4454

4454
44544454

10

10

2907

B

E
C

2907

B

E
C

2907

B

E
C

2907

B

E
C

4454

4454

2222BE

C

2222

BEC

2222BE

C

4454
4454

4454
44544454

4454

2222BE

C

2222BE

C

2222

BEC

10

10

10

2222

BEC

10

10

2222BE

C

2222

BEC

2222BE

C

2222BE

C

4454

2222BE

C

4454

2222BE

C

2222

BEC

2222BE

C

4454

2222BE

C

10

2222

BEC

10

2222BE

C

4454

10

10

1010

10

10

10

4454 4454

4454

4454

4454

4454

10 10

2907

B

E
C

2907

B

E
C

2907

B

E
C

2907

B

E
C

10

10

10

10

2222

BEC

2222BE

C

2222BE

C

4454

2222BE

C

2222BE

C

2222BE

C

2222

BEC

2222BE

C

4454

10

10

4454 4454

4454

4454

4454

4454

2907

B

E
C

2907

B

E
C

2907

B

E
C

2907

B

E
C

CMF0010M

-V

+V

L

N

CMF0010M

-V

+V

L

N

2222

B

E
C

2222

B

E
C

2222

BEC

4454 4454

4454

4454

4454

2222BE

C

2222

BEC

2222BE

C

4454

4454

2907

B

E
C

2907

B

E
C

2907

B

E
C

2907

B

E
C

10

10

4454 4454

4454

4454

4454

4454

2907

B

E
C

2907

B

E
C

2907

B

E
C

2907

B

E
C

+

+ +

++

++

++

+ +

++

++

+

+

+

++

++
++

+

+

++

++

++

+ +

++

++

+ +

++

++
++

+

+

+

+

+

USE 2TER-0327 USE 2TER-0327

AC ONLY AC ONLY

J1 / AUDIO INPUT

J2 / AUDIO OUTPUT

J3 / PTT INPUT J4 / PTT

OUTPUT

S10 - S17 INPUT IMPEDANCE / SUMMING AMPLIFIERS
HI Z | 600

S66 - S89 PTT OUTPUT

DIGITAC

TTL
E/M

S90 - S113 E/M TYPE SELECT

M TYPE I,II,III

(INVERT) / MTYPE IV,V

S18 - S41 PTT PANEL CONTROLS

(UP / RED)

KEY

(CENTER / GREEN = KEY)

NORM

(DOWN / RED) DISABLE

S8 - S9 PTT DISTRIBUTION

ON

OFF

S1 - S7 AUDIO / PTT
DISTRIBUTION

INPUT | BUS

S42 - S65 PTT INPUT

DIGITAC

TTL

E/M

BACKUP

MAIN

MAIN

BACKUP

POWER SUPPLY INDICATORS MAIN |
BACKUP

MAIN

BACKUP

ALARM RELAY

COMPONENT LOCATION DRAWING

2241A Distribution Panel INSTALLATION Section 2

FRONT VIEW

CONVEX 2241A AUDIO / PTT DISTRIBUTION PANEL

KEY
NORMAL
DISABLE

PTT

90-264 VAC

1/2 AMP

BACKUPMAIN

PTT

FUSE FUSE

Repeat the above Audio Check for pins 13/38 of the
Audio Input Connector and pins 13/38, 14/39, 15/40 of
the Audio Output Connector.

Repeat the above Audio Check driving pins 14/39
Repeat the Audio Check for pins 16/41 of the Audio

Input Connector and pins 16/41, 17/42, 18/43 of the
Audio Output Connector.

Repeat the above Audio Check driving pins 17/42
Repeat the Audio Check for pins 19/44 of the Audio

Input Connector and pins 19/44, 20/45, 21/46 of the
Audio Output Connector.

Repeat the above Audio Check driving pins 20/45
Repeat the Audio Check for pins 22/47 of the Audio

Input Connector and pins 22/47, 23/48, 24/49 of the
Audio Output Connector.

Repeat the above Audio Check driving pins 23/48
If any of the audio checks fail, remove the top cover

(per Step 4 on Page 2-4) and check to see that Switches
S1 to S7 are all set to the INPUT position. Refer to the
COMPONENT LOCATION DRAWING on page 2-2 for
the location of S1 - S7.

If any audio check continues to fail with S1 - S7 in the
Input position, replace the top cover. Contact Convex to
arrange for return for warranty repair.

2-3-2 OPERATIONAL CHECK / PTT CIRCUITS

The PTT circuits were tested prior to shipment and will
not generally need to be rechecked prior to installation.
This procedure is provided so that the checks can be
made when needed. The Operational Checks will
require an inexpensive Ohm Meter and a 24 VDC Power
Supply.

Ref page 2-2, PTT Circuit checks assume that all
configuration switches have the factory default settings:

S1 - S7 INPUT = LEFT
24 Front Panel NORM = CENTER
24 INPUT LOGIC E/M = DOWN
24 E/M SEL M I,II,III = UP
S8, S9 DIST = UP
24 OUTPUT LOGIC E/M = DOWN

Connect the Positive output of the 24 Volt Power
Supply to pins 25 and 50 of the PTT INPUT Connector

1713 14 15 16 18 19 20 21 22 23 24121110987654321

REAR VIEW

CONVEX

2241A AUDIO / PTT DISTRIBUTION PANEL

AUDIOOUTPUTOUTPUT INPUTINPUT

S/N

MADE IN USA

(Detector Ground). Connect the Negative output of the
24 Volt Power Supply to each PTT INPUT as it is being
checked. Connect the Ohm Meter across pins 1 and 26
of the PTT OUTPUT Connector.

PTT Check. PTT Input 1 / Outputs 1,2,3 Connect -24
VDC to PTT INPUT 1 (Connector pin 1) and verify that
the Ohm Meter reading across PTT OUTPUT 1 ( pins 1
and 26) is less than 100 Ohms. Verify that the Ohm
Meter reading is greater than 10K Ohms with the -24
Volts removed from PTT Input 1.

Move the Ohm Meter to PTT Output 2 (pins 2 and 27)
and check for < 100 Ohms when -24 V is present and
>10K Ohms when -24 V is removed.

Move the Ohm Meter to PTT Output 3 (pins 3 and 28)
and check for < 100 Ohms when -24 V is present and
>10K Ohms when -24 V is removed.

Repeat the PTT Check for Input 4 / Outputs 4,5,6
Repeat the PTT Check for Input 7 / Outputs 7,8,9
Repeat the PTT Check for Input 10 / Outputs 10,11,12
Repeat the PTT Check for Input 13 / Outputs 13,14,15
Repeat the PTT Check for Input 16 / Outputs 16,17,18
Repeat the PTT Check for Input 19 / Outputs 19,20,21
Repeat the PTT Check for Input 22 / Outputs 22,23,24

If any of the PTT checks fail, remove the top cover and
check to see that all Switches are set to the default
setting. Refer to the COMPONENT LOCATION
DRAWING on page 2-2 for the switch locations.

If any PTT check continues to fail with all switches in
default settings, contact Convex to arrange for return for
warranty repair. Replace the top cover.

2-3-3 Operational Check Alarm Logic. The Alarm
Logic was tested prior to shipment and will not generally
need to be rechecked prior to installation. This
procedure is provided so that the checks can be made
when needed.

Connect an Ohm Meter across pins 25 / 50 of the Audio
Output Connector. Check that the resistance is above
10K Ohm, and that both LEDs on the Front Panel are lit.

Remove the Fuse for the MAIN Supply. Check that the
resistance is less than 100 Ohms, and that the BACKUP
LED is Lit, and the MAIN LED is Off.

POWER SUPPLY

BACKUP

MAIN

2 - 3

2241A Distribution Panel INSTALLATION Section 2

Replace the MAIN Fuse. Check that the resistance is
above 10K Ohm, and that both LEDs on the Front Panel
are lit.
Remove the Fuse for the BACKUP Supply. Check that
the resistance is less than 100 Ohms, and that the
BACKUP LED is Off, and the MAIN LED is Lit.

Replace the BACKUP Fuse. Check that the resistance is
above 10K Ohm, and that both LEDs on the Front Panel
are lit.

If the Alarm Logic fails to operate properly, contact
Convex to arrange for return for warranty repair.

2-4 POWER MODULE REPLACEMENT If it is not
feasible to take the 2241A out of service, a failed power
module can be replaced while the 2241A is in service. A
failed Power module will be indicated by an Alarm
condition (less than 100 Ohms across Audio Output
Connector pins 25/50 ) and the associated LED being
Off.

First check the fuse of the failed supply, and replace if
blown. If the Alarm is still active and LED Off, check the
new fuse to see if it has been blown. If the new fuse is
blown, do not replace it - instead replace the power
modules per the procedure below.

Replacement Power Modules AC UNITS Fuse
AC to 12VDC: Astrodyne Model AFC-12S 1/2
A
12 VDC to +/-12VDC: Astrodyne Model EC6A05
12 VDC to +5 VDC: Astrodyne Model EC6A01

4. Remove six screws from the top of the unit, three
screws from the front, three screws from the rear, and
remove the top cover. Refer to the drawing on Page 2-2
for the locations of the power modules.

5. Note the warning above, and the orientation of the
modules. Remove all power modules associated with
the failed supply by pulling straight up. Check the pin
alignment on the replacement modules and install.
Press straight down to seat the replacement power
modules. (Bumpers on the top cover keep the power
module seated in the socket.)

6. Replace the fuse associated with the failed power
modules. Check that the alarm condition has been
released (greater than 10K Ohms across Audio Output
Connector pins 25/50 ) and that both Power LEDs are lit.

7. Replace the top cover and install six screws in the
top. Install three screws on the front and rear panels that
hold the top cover on.

8. Slide the 2241A back into the cabinet, and install four
mounting screws in the rack mounting ears. Check that
all cabling to the rear panel is secure.

9. Test the individual power modules removed from the
2241A to determine which of the two or three units is
defective. Replace the defective unit so that there is a
complete set of spares available.

2-5 INSTALLATION. Installation consists of:
configuration of internal switches, mounting, connection
of signal and power, and system testing.

Replacement Power Modules 12 VDC Units Fuse
12 VDC to +/-12VDC: Astrodyne Model EC6A05 2.0 A
12 VDC to +5 VDC: Astrodyne Model EC6A01

Replacement Power Modules 24 VDC Units Fuse
24 VDC to +/-12VDC: Astrodyne Model EC6A15 1.0 A
24 VDC to +5 VDC: Astrodyne Model EC6A11

Replacement Power Modules 48 VDC Units Fuse
24 VDC to +/-12VDC: Astrodyne Model EC6A25 1/2 A
24 VDC to +5 VDC: Astrodyne Model EC6A21

POWER MODULE REPLACEMENT PROCEDURE
WARNING. To avoid electric shock when replacing a

power module while the 2241A Panel is in service, take
extreme care not to touch any of the traces on the
printed circuit board or any wiring.

1. Remove the fuse associated with the failed power
modules.

2. Check that the rear panel signal and power
connectors are secure.

3. Remove four screws from the rack mounting ears,
and slide the 2241A straight forward out of the cabinet
being careful not to release power or signal connections.
Set the 2241A down on a flat surface.

2-5-1 SWITCH CONFIGURATION. Refer to the 2241A
Block Diagram and Component Location Drawing on
Page 2-2. Remove the top cover. ( Three screws on the
rear and front panels, and six screws on the top of the
2241A. )

Audio Distribution S1-S7 Audio Distribution is
controlled by Switches S1 to S7. Factory default
settings have all of these switches set to the INPUT
(LEFT) Position. With the default settings, each audio
input will be distributed to three outputs. The default
configuration provides a total of 8 Inputs - each of which
is distributed to 3 Outputs.

(1 to 3 ) x 8 => S1-S7 all INPUT / LEFT
(1 to 6) x 4 => S1,3,5,7 = BUS / RIGHT

S2,4,6 = INPUT / LEFT

(1 to 12) x 2 => S1,2,3,5,6,7 = BUS / RIGHT

S4 = INPUT / LEFT

(1 to 24) x 1 => S1,2,3,4,5,6,7 = BUS /

RIGHT

Other combinations of three outputs are possible. For
example (1 to 9) x 2 plus (1 to 6) x 1. Refer to the
2241A Block Diagram ON PAGE 2-2 or 2-5 for
guidance.

2 - 4

2241A Distribution Panel INSTALLATION Section 2

FRONT VIEW

CONVEX 2241A AUDIO / PTT DISTRIBUTION PANEL

KEY
NORMAL
DISABLE

PTT

90-264 VAC

1/2 AMP

1/26
2/27 2

4/29
5/30 5

7/32
8/33

10/35
11/36

13/38
14/39

22/47
23/48

B1

HI Z

S1A

S10

600

IN4

4

B2

HI Z

S2A

S11

600

IN7

7

B3

8

HI Z

S3A

S12

600

IN10

10
11

B4

HI Z

S13

S4A

600

IN13

13

B5

14

HI Z

S5A

S14

600

IN16

1616/41

B6

1717/42

HI Z

S6A

S15

600

IN19

1919/44

B7

2020/45

HI Z

S7A

S16

600

IN22

22
23

HI Z

S17

600

600 OHM, BALANCED RECEIVERS / DRIVERS

AUDIO

BUS 1

BACKUPMAIN

FUSE FUSE

1
2
3

4
5
6

7
8
9

10
11
12

13
14
15

16
17
18

19
20
21

22
23
24

PINSOUTPUTINPUTPINS

10/35
11/36
12/37

13/38
14/39
15/40

16/41
17/42
18/43

19/44
20/45
21/46

22/47
23/48
24/49

1 1

1/261

2 2

2/27

3 3

3/28

4/29
5/30
6/31

7/32
8/33

9/34

S1B

4 4
5 5
6 6

S2B

7 7
8 8

9 9

S3B

10 10
11 11
12 12

S4B

13 13
14 14
15 15

S5B

16 16
17 17
18 18

S6B

19 19
20 20
21 21

S7B

22 22
23 23
24 24

PTT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PUSH TO TALK CIRCUITS

PTT

OUTPUT / PINSPINS / INPUT

BLOCK DIAGRAM / 2241A AUDIO / PTT DISTRIBUTION PANEL

25,50

26-49

-48/SB

DET GND

1-24
PTT IN

10K

INPUT
LOGIC

+12 +12+5 +5E/M

(STATION BATTERY)

DETECT

S90-S113

KEY

S42-S65

TTL

DIG

DIST IN

E/M SEL
M:I,II,III

M:IV,V,E
(INVERT)

ON

S8,S9

OFF

DIST OUT

BLOCK DIAGRAM / PTT CIRCUIT

S18-S41

PTT
CONTROL

RED

RED

(FRONT PANEL)

KEY

NORM

DISABLE

PTT OUT

1-24

DET GND

PTT

OUTPUT

25,50

10K

LOGIC

S66-S89

E/M

TTL

DIG

26-49

GND/SG

AUDIO SUM INPUT IMPEDANCE Switches. Set the
Sum Input Impedance switches to HI Z only when a
Sum Input is in use and bridging an external load.
Otherwise set to 600 Ohm Termination. ( RIGHT )

PTT Distribution S1-S7, S8, S9 PTT Distribution
“tracks” the Audio Distribution when S8 and S9 are set
to DIST ON ( UP ).

PTT Buffering S8, S9 PTT Buffering is used to provide
a high output current capable of directly keying
transmitters for every PTT Input. PTT Distribution can
be turned OFF to permit PTT Buffering. Switch S8
controls PTT Outputs 1-12. S9 controls PTT Outputs 13-

24. When PTT Distribution is turned OFF, S1-S7

continue to control Audio Distribution, but have no

1713 14 15 16 18 19 20 21 22 23 24121110987654321

REAR VIEW

CONVEX

2241A AUDIO / PTT DISTRIBUTION PANEL

AUDIOOUTPUTOUTPUT INPUTINPUT

S/N

MADE IN USA

effect on PTT Distribution. In this case each PTT
Output tracks its individual Input.

PTT Logic Conversion PTT Logic conversion permits
dissimilar equipment to be interfaced. For example a
console with TTL Logic can be interfaced to a mux with
E/M Logic. In this case the PTT Input Logic would be set
for TTL, and the PTT Output would be set for E/M.

PTT Circuit Switches. There are four internal switches
that are used to setup PTT Operation. Two of the four
set the PTT Logic used at the Input and Output. The
Third switch selects the E/M Type ( or it is used to invert
TTL or Digitac Logic). and the fourth switch determines
if multiple PTT Outputs are to be distributed from
individual PTT Inputs. The operational PTT Control is
located on the front panel. Note: Refer to the

Component Location Drawing on Page 2-2.

1. Set the PTT INPUT LOGIC Switch to accommodate
the type of logic driving the 2241A. The choices are:
E/M, TTL, and Digitac.

2. Set the E/M SELECTOR Switch for the appropriate
type. Use M: I,II,III for M Lead types I,II, or III or normal
TTL / Digitac operation. Use M: IV,V, E for E Leads or
type IV, or V M Leads, or to invert TTL, or Digitac Logic.

3. Set the DISTRIBUTION Switches to ON or OFF.

Note that there are two DISTRIBUTION Switches on the
2241A. One controls PTT Outputs 1-12, and the other
controls PTT Outputs 13-24. Set the DISTRIBUTION

Switches to ON for PTT Distribution that ‘tracks” the
AUDIO Distribution. Set the DISTRIBUTION Switches to
OFF for each PTT Output to track its INPUT.

4. Set the PTT OUTPUT LOGIC Switch to
accommodate the type of logic that the 2241A is driving.
The choices are: E/M, TTL, and Digitac.

TOP COVER. When all of the internal configuration
switches have been set, replace the top cover of the
2241A. There are three screws in the front and rear
panels, and six screws on top.

2-5-2 MOUNTING. If the rear panel of the 2241A will be
obstructed by other equipment in the cabinet, connect
signal and power cables prior to mounting. See Section

POWER SUPPLY

BACKUP

MAIN

2 - 5

2241A Distribution Panel INSTALLATION Section 2

2-5-3. Use four screws in the mounting ears on the
panel to secure the 2241A in an equipment cabinet or
rack.

2-5-3 SIGNAL AND POWER CONNECTIONS. All
Audio, PTT, and Power Leads connect to the rear panel
of the 2241A.

LOCAL RADIOSTO REMOTE RADIOS

Tx AUDIO

2241A AUDIO / PTT DISTRIBUTION PANEL

PTT

Tx AUDIO

T1 MUX

UP TO 8 SUM INPUTSUP TO 8 Tx INPUTS

Rx AUDIO

DISPATCH CONSOLE

UP TO 24 PTT OUTPUTSUP TO 24 Tx OUTPUTS

M LEAD / PTT

1713 14 15 16 18 19 20 21 22 23 24121110987654321

M LEAD / PTT

PTT PTTTx Tx

CONVEX 2241A AUDIO / PTT DISTRIBUTION PANEL

UP TO 24 PTT INPUTS

KEY
NORM
DISABLE

VOTER

POWER

BUMAIN

Audio Inputs. Connect up to 8 Audio Inputs to the
AUDIO INPUT Connector on the far right of the rear
panel. Refer to the 2241A Block Diagram on Page 2-5
for pin assignments.

Audio Sum Inputs. Connect up to 8 Audio Sum Inputs
to the AUDIO INPUT Connector on the far right of the
rear panel. Refer to the 2241A Block Diagram on Page
2-5 for pin assignments.

Audio Output. Connect up to 24 Audio Outputs to the
AUDIO OUTPUT Connector on the rear panel. Refer to
the 2241A Block Diagram on Page 2-5 for pin
assignments.

PTT Inputs. Connect the PTT Inputs to the PTT INPUT
Connector on the rear panel. Refer to the 2241A Block
Diagram on Page 2-5 for pin assignments.

PTT Outputs. Connect the PTT Outputs to the PTT
OUTPUT Connector on the rear panel. Refer to the
2241A Block Diagram on Page 2-5 for pin assignments.

Power Leads. For DC Units, check the polarity of the
power leads, then turn the DC Power Supply OFF and
connect the power leads to the terminal block on the far
left of the rear panel. Turn the DC Power Supply ON,
and check that both LEDs on the front of the 2241A are
lit.

AC Units have an integral power cord. If necessary,
change the plug on the AC Power cord to accommodate
local power mains receptacles.

2-5-4 SYSTEM TESTING This section is very general in
order to accommodate a variety of situations. Set all of
the front panel switches to the NORM Position.

Audio Distribution. Check that individual audio signals
are being distributed to the proper points, and check that
each output is the proper level. Assuming that the Front
Panel Gain Controls have not been adjusted, the 2241A
has 0 dB gain when being driven with a 600 Ohm
Source, and with the outputs terminated with 600 Ohms.

SUM Audio Distribution. Check that individual sum
audio signals are being distributed to the proper points.

PTT Distribution. Check that individual leads are being
distributed to the proper points. Check that each PTT
Output is being properly keyed from the dispatch
console.

PTT Override. Check that the front panel switches on
the 2241A provide override control of each transmitter.

In the KEY Position the transmitter should Key
independent of the status of the dispatch console and
the switch bat should light up RED.

In the DISABLE Position, the transmitter should remain
Idle independent of the status of the dispatch console,
and the switch bat should light up RED .

Set all of the front panel switches to the NORM Position,
and verify that all transmitters are tracking key
commands issued by the dispatch console. Note that the
switch bats light up GREEN when PTT is asserted from
the console.

2-6 SUPPORT We invite your comments, questions or
technical support requirements. Please check our

website for the current address and phone numbers.

www.ConvexCorp.com

e-mail: [e-mail]
Phone [phone] / FAX [phone]

If repair work is required, ship the product to the factory:

CONVEX CORPORATION

1319 Shepard Drive

Sterling, VA 20164 USA

(Check www.ConvexCorp.com for current information.)

Include a note: Trouble description

Your name / phone number
Return shipping address

2-7 WARRANTY All Convex products are warranted
to be free of manufacturing defects for a period of one
year from the date of shipment.

2-8 PRODUCT REPAIR SERVICE Post warranty
repair service is available for Convex products. Convex
will advise as to the nature and cost of repair and,
subject to customer instructions, will promptly repair and
return the product.

2 - 6

2241A Distribution Panel OPERATION Section 3

FRONT VIEW

CONVEX 2241A AUDIO / PTT DISTRIBUTION PANEL

KEY
NORMAL
DISABLE

PTT

90-264 VAC

1/2 AMP

BACKUPMAIN

PTT

FUSE FUSE

3-1 INTRODUCTION This section discusses operation
of the 2241A Audio / PTT Distribution Panel. The 2241A
provides a compact means of distributing audio and
Push to Talk (PTT) signals to as many as 24 base
stations. In addition, it provides manual PTT override for
individual transmitters. 24 front panel switches permit
each radio to be keyed, disabled, or to track normal
console control. Manual PTT control is used for
installation and management of radio networks. It is also
used to align simulcast networks by enabling one
transmitter at a time to perform delay measurements.

LOCAL RADIOSTO REMOTE RADIOS

Tx AUDIO

T1 MUX

M LEAD / PTT

PTT PTTTx Tx

UP TO 24 PTT OUTPUTSUP TO 24 Tx OUTPUTS

2241A AUDIO / PTT DISTRIBUTION PANEL

PTT NORM

UP TO 8 SUM INPUTSUP TO 8 Tx INPUTS

Tx AUDIO

Rx AUDIO

M LEAD / PTT

DISPATCH CONSOLE

CONVEX 2241A AUDIO / PTT DISTRIBUTION PANEL

1713 14 15 16 18 19 20 21 22 23 24121110987654321

UP TO 24 PTT INPUTS

KEY
DISABLE

VOTER

POWER

BUMAIN

3-2 AUDIO DISTRIBUTION Audio Distribution is
configured by seven, internal Distribution Switches
during installation per Section 2-5-1. Typically, each
radio channel will be distributed to each transmitter site.
The block diagram in the right column shows the
Distribution Switches set for four inputs. Input 1 is
distributed to 12 Outputs, Input 13 is distributed to 6
Outputs, and Inputs 19 and 22 are distributed to 3
Outputs each. Although the Distribution Switches may
be reconfigured if the network is changed, they are not
controlled during normal operation.

3-3 AUDIO GAIN CONTROLS Front Panel Audio Gain
Controls, are used to normalize the deviation of each
transmitter using a test receiver. Front Panel PTT
Controls are used to disable PTT to any base station
that interferes with the channel / site being aligned.
Since the gain control has a range of +/- 10 dB, care
should be taken not to overdrive any equipment “down
stream” from the 2241A.

3-4 PTT DISTRIBUTION Per the block diagram below,
PTT Distribution is also configured with the Audio

1713 14 15 16 18 19 20 21 22 23 24121110987654321

REAR VIEW

CONVEX

2241A AUDIO / PTT DISTRIBUTION PANEL

AUDIOOUTPUTOUTPUT INPUTINPUT

S/N

MADE IN USA

Distribution Switches. The internal PTT configuration
switches are not controlled during normal operation.

3-5 FRONT PANEL / PTT CONTROLS . Front Panel
PTT Switches are also not controlled during normal
operation. They are usually set to the NORM Position so
that the dispatch console determines transmitter keying.
The PTT Switches are used during system installation,
routine maintenance checks, trouble shooting, and for
special situations requiring rapid adaptation of the
network. PTT Switch bats are lighted RED to indicate an
abnormal condition such as KEY or DISABLE. In the
Normal Position, switch bats lighted GREEN to indicate
that PTT is asserted.

3-5-1 INSTALLATION AND MAINTENANCE . A typical
installation or maintenance application is to shut down

1/26
2/27 2

4/29
5/30 5

7/32
8/33

10/35
11/36

13/38
14/39

22/47
23/48

DET GND

25,50

1-24
PTT IN

26-49

-48/SB

B1

HI Z

S1A

S10

600

IN4

4

B2

HI Z

S2A

S11

600

IN7

7

B3

8

HI Z

S3A

S12

600

IN10

10
11

B4

HI Z

S13

S4A

600

IN13

13

B5

14

HI Z

S5A

S14

600

IN16

1616/41

B6

1717/42

HI Z

S6A

S15

600

IN19

1919/44

B7

2020/45

HI Z

S7A

S16

600

IN22

22
23

HI Z

S17

600

600 OHM, BALANCED RECEIVERS / DRIVERS

KEY

DETECT

10K

INPUT
LOGIC

+12 +12+5 +5E/M

(STATION BATTERY)

AUDIO

BUS 1

BLOCK DIAGRAM / 2241A AUDIO / PTT DISTRIBUTION PANEL

S90-S113

S42-S65

TTL

DIG

PINSOUTPUTINPUTPINS

1/261

1

2/27

2

3/28

3

4/29

4

5/30

5

6/31

6

7

7/32
8/33

8

9/34

9

10

10/35

11

11/36

12

12/37

13

13/38

14

14/39

15

15/40

16

16/41

17

17/42

18

18/43

19

19/44

20

20/45

21

21/46

22

22/47

23

23/48

24

24/49

DIST IN

E/M SEL
M:I,II,III

M:IV,V,E
(INVERT)

ON

S8,S9

OFF

DIST OUT

BLOCK DIAGRAM / PTT CIRCUIT

S1B

S2B

S3B

S4B

S5B

S6B

S7B

PUSH TO TALK CIRCUITS

KEY
NORM
DISABLE

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

PTT CIRCUIT

1 1
2 2
3 3

4 4
5 5
6 6

7 7
8 8

9 9

10 10
11 11
12 12

13 13
14 14
15 15

16 16
17 17
18 18

19 19
20 20
21 21

22 22
23 23
24 24

PTT
CONTROL

RED

S18-S41

RED

(FRONT PANEL)

3- 1

POWER SUPPLY

BACKUP

MAIN

OUTPUT / PINSPINS / INPUT

PTT

PTT

OUTPUT
LOGIC

E/M

PTT OUT

1-24

DET GND

25,50

10K

S66-S89

TTL

DIG

26-49

GND/SG

2241A Distribution Panel OPERATION Section 3

transmitters at all sites except one for purposes of
testing the one site. In this case, operation of the PTT
Switches insures which transmitters will remain OFF and
which transmitter will be keyed - independent of
commands that the dispatch console may give. This
provides an opportunity to test both the “Talk Out” and
“Talk In” equipment without interference from other
transmitters.

This technique can also be used to keep a channel open
for testing in situations where the dispatch console
imposes a time limit on transmissions. In some
simulcast systems, equalizers are required to match the
phase and amplitude responses of “talk out” links to
each site. This requires that the response of the links to
each site be measured. In order to do this, one site is ­in turn -made operational and all interfering sites are
turned off.

All simulcast systems require the transmission delay to
each site be measured so that individual audio delay
lines can be precisely adjusted. Delay lines are set so
that audio delay from multiple sites is the same in those
geographical areas where transmitter coverage overlap.
Typically this is done by measuring the “Round Trip
(audio) Delay” to a test receiver, with one site active at a
time. The PTT Switches provide a convenient and sure
means of controlling this process.

FINAL NOTE Features found in all Convex Products
are the result of feedback from current and prospective
customers. Please tell us what you would like improved
or changed. We appreciate your suggestions.

Please check our website for the current address
and phone number.

www.convexcorp.com

e-mail: [e-mail]
Phone [phone] / FAX [phone]

CONVEX CORPORATION

1319 Shepard Drive

Sterling, VA 20164 USA

Advertisement

Convex also manufactures precision audio delay
lines
( Models 2046 and VDL-2M Simulcast Delay Lines)

and Delay Measuring, TIMS Test Sets (Model 806A).

3-5-2 TROUBLE SHOOTING The PTT Switches can
be used for trouble shooting the network. Since
individual transmitters can be controlled, the PTT
Switches can be used to isolate a problem to a particular
site or base station. Once having isolated a problem
situation, that site or radio can be amputated by setting
it’s PTT Switch to DISABLE until repairs have been
made.

3-5-3 SPECIAL CASES / ADAPTATION. PTT Switches
can also be used to rapidly adapt the network for special
situations. An alternate or backup site can be enabled in
the event a failure or accident at the primary site. A site
or a channel can be silenced to permit a neighboring
jurisdiction temporary use of a channel (frequency) to
handle a special situation.

3 - 2