2241A Distribution Panel
OPERATION
Section 3
3- 1
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.
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
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
REAR VIEW
FRONT VIEW
CONVEX 2241A AUDIO / PTT DISTRIBUTION PANEL
CONVEX
2241A AUDIO / PTT DISTRIBUTION PANEL
BACKUP
MAIN
1/2 AMP
90-264 VAC
POWER SUPPLY
BACKUP
DISABLE
NORMAL
KEY
PTT
MAIN
MADE IN USA
S/N
17
13
14
15
16
18
19
20
21
22
23
24
12
11
10
9
8
7
6
5
4
3
2
1
PTT
AUDIO
OUTPUT
OUTPUT
INPUT
INPUT
FUSE
FUSE
UP TO 24 PTT OUTPUTS
UP TO 24 Tx OUTPUTS
UP TO 8 SUM INPUTS
UP TO 8 Tx INPUTS
UP TO 24 PTT INPUTS
VOTER
Rx AUDIO
M LEAD / PTT
2241A AUDIO / PTT DISTRIBUTION PANEL
BU
MAIN
CONVEX 2241A AUDIO / PTT DISTRIBUTION PANEL
17
13
14
15
16
18
19
20
21
22
23
24
12
11
10
9
8
7
6
5
4
3
2
1
DISABLE
KEY
PTT
NORM
POWER
M LEAD / PTT
T1 MUX
DISPATCH CONSOLE
LOCAL RADIOS
TO REMOTE RADIOS
Tx AUDIO
Tx AUDIO
PTT
PTT
Tx
Tx
10K
10K
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
S66-S89
S8,S9
S18-S41
S42-S65
S90-S113
S7B
S6B
S5B
IN22
S7A
B7
IN19
S6A
B6
IN16
S5A
B5
IN13
S4A
B4
IN10
S3A
B3
S4B
S3B
S2B
S1B
IN7
S2A
B2
IN4
S1A
B1
BUS 1
(STATION BATTERY)
S17
S16
S15
S14
S13
S12
S11
S10
M:IV,V,E
M:I,II,III
HI Z
HI Z
HI Z
HI Z
HI Z
HI Z
HI Z
HI Z
600
600
600
600
600
600
600
600
GND/SG
26-49
1-24
PTT OUT
BLOCK DIAGRAM / PTT CIRCUIT
-48/SB
26-49
PTT IN
1-24
25,50
DET GND
E/M SEL
DETECT
KEY
INPUT
LOGIC
CONTROL
PTT
OUTPUT
PTT
LOGIC
DET GND
25,50
(FRONT PANEL)
RED
RED
DISABLE
NORM
KEY
OFF
ON
DIST OUT
DIST IN
(INVERT)
+12
+12
+5
+5
E/M
E/M
TTL
TTL
DIG
DIG
23
22
23/48
22/47
20
20/45
19
19/44
17
17/42
16
16/41
14
13
14/39
13/38
11
10
8
7
11/36
10/35
8/33
7/32
12
11
10
9
8
7
5/30
5
4
2/27
2
BLOCK DIAGRAM / 2241A AUDIO / PTT DISTRIBUTION PANEL
PUSH TO TALK CIRCUITS
OUTPUT / PINS
PINS / INPUT
24
23
22
21
20
19
18
17
16
15
14
13
600 OHM, BALANCED RECEIVERS / DRIVERS
24
24
23
23
22
22
21
21
20
20
19
19
18
18
17
17
16
16
15
15
14
14
13
13
PTT
12
12
11
11
10
10
9
9
8
8
7
7
6
6
5
5
4
4
3
3
2
2
1
1
AUDIO
4/29
24/49
23/48
22/47
21/46
20/45
19/44
18/43
17/42
16/41
15/40
14/39
13/38
PINS
OUTPUT
INPUT
PINS
1/26
12/37
11/36
10/35
9/34
8/33
7/32
6/31
5/30
4/29
3/28
2/27
1/26
1
6
5
4
3
2
1
