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Motorola MSF5000 SSCB Signals Compiled by Robert W. Meister WA1MIK (Originally created 13-Sep-06. Revised and added all connectors 23-May-12. Added all other signals 18-Jan-21.)

This is a compilation of the signals on the SSCB schematic. The entire SSCB section from a UHF station service manual has been scanned and can be found here as a 1.3MB PDF file. The page numbers shown in the tables below reference the schematic diagram page (1-9 of 9 pages), NOT the PDF file page. Most of the pages were fold-out and were scanned as two separate halves, but everything is present.

Notes for all tables:

1. An asterisk (*) after a signal name indicates active low (to ground).
2. Src = page number where signal originates or enters via a connector.
3. Dst = page number(s) that signal goes to leaves via a connector.

SSCB Schematic Signals:

This table shows all of the signals that travel between schematic pages or enter or leave the SSCB.

Abbreviations used in the "Notes" column:

1. DISPLAY = signal used for front panel display.
2. EEPOTS = signal used for all Electronically Erasable Potentiometers.
3. EEPOT n = signal used for one specific EEPOT.
4. LED = LED on front of SSCB.
5. POST = used primarily for Power On Self Tests.
6. SWITCH = front-panel toggle switch.

Signal Name	Src	Dst	Notes
+5V	2	LOTS
+9.6V	2	LOTS	J801
ACCESS DISABLE*	3	4	SWITCH
AGC REF	8	8	800/896 MHZ ONLY
ALERT TONE 0..3	4	1
ALERT TONE AUDIO	1	6,8
ALERT TONE LINE GATE	5	6
ALERT TONE SAMPLE	1	3	POST
ALERT TONE TX GATE	5	6,7
ANTENNA RELAY ENABLE*	5	J801
AUX +13.8V	2	LOTS	J701, A++
BA* 0..3	4	LOTS
BATTERY REVERT*	3	4
BD* 0..3	4	LOTS
CHAN ACT	9	3
CODED MOD AUDIO	7	7
CODED MOD AUDIO_1	1	7
CODED MOD LEVEL*	4	J803
CODED RX LEVEL*	4	J803
COMPANDOR ENABLE	4	7,9
CT AUDIO	1	J804	J804
CT SELECT		1
DELAYED RESET	3	4
DIGIT 1..3	3	1	DISPLAY
DISABLE*	5	5	LED
DISPLAY CHANGE*	3	4	SWITCH
DISPLAY ON	3	1
DISPLAY SELECT*	3	4	SWITCH
DIVERSITY AUDIO	8	8
DS*	4	LOTS
EXPANSION RESET*	3	3
FAST KEY	1	3
FF ENABLE	4	8,9
FF LEVEL*	4	8	EEPOT 1
FWD PWR	1	3
GCC DATA AUDIO	7	7
HSR signals	5	5
IPCB INTERFACE	3	3
LEVEL INC	4	7,8,9	EEPOTS
LEVEL U/D*	5	7,8,9	EEPOTS
LINE AUDIO	6	7
LINE AUDIO SAMPLE	7	3	POST
LOCAL AUDIO	6	6
LOCAL GATE	5	6
LOOPBACK	5	8
MAX DEV LEVEL*	4	7	EEPOT 4
MIC AUDIO	6	6
MIC PTT*	3	4	J812
MOD AUDIO SAMPLE	7	3	POST
MPTSQ	9	1,5
MRTI AUDIO IN	6	6
MRTI AUDIO OUT	6	7
MRTI AUX INDICATE	5	J802
MRTI GATE	5	6
MRTI INHIBIT	5	J802
MRTI MONITOR*	3	4
MRTI PL STRIP*	3	4
MRTI PTT*	3	4
MRTI RX CARRIER	5	J802
MUTE	3	3
NORMALIZED IF ENVELOPE	8	8	800/896 MHZ ONLY
OVERVOLTAGE ALARM*	3	4
PA FULL POWER*	3	4	LED
PA KEY*	5	J801	LED
PA ON*	3	4	LED
PA POWER CUTBACK*	5	J801
PL AUDIO SAMPLE	1	3	POST
PL DECODE DATA	8	3
PL DISABLE*	3	4
PL ENCODE AUDIO	1	7
PL/CT 0..3	4	1
PL/CT SELECT	4	1
PL/DPL*	5	8
PREDE/FLAT*	4	7,9
QUAD AUDIO	9	9
QUAD1 AUDIO	9	9
QUAD2 AUDIO	9	9
RAC_LN_AUD	6	6
RAW RX1 AUDIO	8	8
RAW RX2 AUDIO	8	8
RAW TX AUDIO	6	7
RAW/TX	7	7
RCVR SQ LEVEL*	4	9	EEPOT 3
REPEATER GATE	5	6
RESET*	2	3
RESET_SWITCH*	3	2	SWITCH
RFL PWR	1	3
RPTR SQ LEVEL*	4	9	EEPOT 2
RPTR UNSQ	9	3
RX LEVEL*	4	8	EEPOT 5
RX1 AUDIO	9	6
RX1 AUDIO SAMPLE	9	3	POST
RX1 GATE	5	6
RX1 LOCK*	3	4	LED
RX1 LOOP	3	4
RX1 STROBE	5	J801
RX1 UNSQ	9	3
RX1*/RX2	4	8
RX2 AUDIO	6	6
RX2 LOCK*	3	4
RX2 STROBE	5	J801
SA 0..2	4	J801
SD 0..3	4	J801
SECURE ALERT TONES	6	6
SECURE RX AUDIO	6	6
SEGMENT a..g,dec	4	1	DISPLAY
SELECT AUDIO	6	7
SHUTSOWN*	2	J800	+5V
SPKR AUDIO	7	J812
SQ ADAPT	5	9
SQUELCH EEPOT ENABLE*	4	9
SYSTEM AUDIO SAMPLE	7	3	POST
TKG MOD AUDIO	7	7
TX AUDIO	6	7
TX DATA AUDIO	7	7
TX GATE	5	6
TX LOCK*	3	4	LED
TX LOOP	3	4
TX MOD AUDIO	7	7
TX STROBE	5	J801
VA (4.8V)	2	LOTS
VB (4.8V)	2	LOTS
VC (4.4V)	2	LOTS
VD (3.8V)	2	LOTS
VE (5.1V)	2	LOTS
XMIT*	3	4	SWITCH

Expansion Connector J800 Signals:

This two-row connector is found on top of the plastic control tray, into which you can attach an expansion tray, a programming cable, or a metering panel.

Pin	Signal Name	Src	Dst
1	A++	2	2
2	A++	2	2
3	A++	2	2
4	A++	2	2
5	A++	2	2
6	AUDIO GND	2	2
7	AUDIO GND	2	2
8	AUDIO GND	2	2
9	AUDIO GND	2	2
10	AUDIO GND	2	2
11	IPCB	3	3
12	EXPANSION RESET*	3	3
13	BA0	4	4
14	BA1	4	4
15	BA2	4	4
16	BA3	4	4
17	BD0*	4	4
18	BD1*	4	4
19	BD2*	4	4
20	BD3*	4	4
21	LOGIC GND	2	2
22	DS*	4	4
23	SHUTDOWN*	2	2
24	LOGIC SPARE	1	1
25	LOGIC SPARE	1	1
26	AUDIO SPARE	1	1
27	AUDIO SPARE	6	6
28	GEN TX DATA	1	1
29	QUAD 2 AUDIO	9	9
30	DIVERSITY AUDIO	8	8
31	GCC/RAC DATA AUDIO	7	7
32	SELECT AUDIO	6	7
33	LOCAL AUDIO	6	6
34	TX DATA AUDIO	7	7
35	RX2 AUDIO	6	6
36	TX AUDIO	6	7
37	AUDIO GND	2	2
38	RX1 AUDIO	9	9
39	QUAD 1 AUDIO	9	9
40	AUDIO GND	2	2

RF Tray Connector J801 Signals:

This two-row connector feeds signals to and from the RF Tray through a flat cable.

Pin	Signal Name	Src	Dst
1	+9.6V	2	2
2	RX2 LOCK*	3	4
3	TX MOD AUDIO	7	7
4	AUDIO GND (GND A)	2	2
5	RAW RX1 AUDIO	8	8
6	RAW RX2 AUDIO	8	8
7	ANTENNA RELAY ENABLE*	4	5
8	TX LOCK*	3	4
9	RX2 STROBE	4	5
10	PA FULL POWER*	3	4
11	AGC REF* (800/896)	8	8
12	PA ON*	3	4
13	RX1 LOOP	3	4
14	PA KEY*	4	5
15	RX1 LOCK*	3	4
16	POWER CUTBACK*	4	5
17	SD0	4	4
18	TX LOOP	3	4
19	SD1	4	4
20	SA2	4	4
21	SD2	4	4
22	SA1	4	4
23	SD3	4	4
24	SA0	4	4
25	RX1 STROBE	4	5
26	TX STROBE	4	5

MRTI Connector J802 Signals:

This single-row connector can either be 14 or 20 pins, and the layout is slightly different.

Pin	Pin	Signal Name	Src	Dst
1	1	LOGIC GND	2	2
2	2	MRTI PL STRIP*	3	4
3	3	LOGIC GND	2	2
4	4	MRTI MONITOR*	3	4
5	5	MRTI PTT*	3	4
6	6	LOGIC GND	2	2
7	7	AUDIO GND	2	2
8	8	MRTI AUDIO IN	6	6
9	9	LOGIC GND	2	2
10	10	MRTI AUDIO OUT	6	7
11	11	MRTI RX CARRIER	4	5
12	12	MRTI INHIBIT	4	5
13	---	N.C.	--	--
14	14	MRTI AUX INDICATE	4	5
15	---	N.C.	--	--
16	---	A++	2	2
17	---	A++	2	2
18	13	AUDIO GND	2	2
19	---	N.C.	--	--
20	---	N.C.	--	--

Secure Board Connector J803 Signals:

This two-row connector feeds the secure board that mounts on plastic standoffs on top of the SSCB board.

Pin	Signal Name	Src	Dst
1	AUDIO GND	2	2
2	AUDIO GND	2	2
3	+9.6V	2	2
4	SECURE RX AUDIO	6	6
5	TX AUDIO	6	7
6	RAW TX AUDIO	6	7
7	CODED MOD AUDIO	7	7
8	LOCAL AUDIO	6	7
9	HSR IN	4	5
10	LOGIC GND	2	2
11	HSR TO SECURE	4	5
12	LOGIC GND	2	2
13	HSR CLOCK	4	5
14	LOGIC GND	2	2
15	HSR SYN	4	5
16	LOGIC GND	2	2
17	BD3*	4	4
18	BD2*	4	4
19	BD1*	4	4
20	BD0*	4	4
21	BA3	4	4
22	BA2	4	4
23	BA1	4	4
24	BA0	4	4
25	DS*	4	4
26	N.C.	1	1
27	QUAD AUDIO	9	9
28	IN MRTI AUDIO	6	7
29	IPCB	3	3
30	LEVEL U/D*	4	5
31	LEVEL INC	4	4
32	CODED MOD LEVEL*	4	4
33	EXPANSION RESET*	3	3
34	SECURE ALERT TONES	6	6
35	CODED RX LEVEL*	4	4
36	N.C.	1	1
37	KEY BATTERY GND	2	2
38	CODED MOD AUDIO_1	1	7
39	+5V	2	2
40	AUDIO GND	2	2

TTRC Board Connector J804 Signals:

This two-row connector feeds the Trunked Tone Remote Control (TTRC) cards that install in the plastic control tray.

Pin	Signal Name	Src	Dst
1	A++	2	2
2	AUDIO GND	2	2
3	9.6V	2	2
4	LINE AUDIO	6	7
5	TX AUDIO	6	7
6	RAW TX AUDIO	6	6
7	TKG MOD AUDIO	7	7
8	QUAD AUDIO	9	9
9	HSR OUT	4	5
10	LOGIC GND	2	2
11	HSR FROM TTRC	4	5
12	LOGIC GND	2	2
13	HSR CLOCK	4	5
14	LOGIC GND	2	2
15	HSR SYN	4	5
16	LOGIC GND	2	2
17	BD3*	4	4
18	BD2*	4	4
19	BD1*	4	4
20	BD0*	4	4
21	BA3	4	4
22	BA2	4	4
23	BA1	4	4
24	BA0	4	4
25	DS*	4	4
26	IPCB	3	3
27	CONNECT TONE AUDIO	1	1
28	EXPANSION RESET*	3	3
29	MUTE	3	3
30	GEN TX DATA	1	1
31	+5V	2	2
32	A++	2	2
33	+5V	2	2
34	AUDIO GND	2	2

Forward/Reflected Power Connectors J806/J807 Signals:

These are female RCA jacks that are fed via coaxial cables from the forward/reflected power sensor present on 800 and 896 MHz and trunking stations. They are found on page 1 of the SSCB schematic and merely go through some op-amp buffers.

Control/Microphone Connector J812 Signals:

This 6-position, 6-contact (6P6C) modular jack is used for a local microphone, handset, or programming cable.

Pin	Signal Name	Src	Dst
1	LOGIC GND	2	2
2	AUDIO GND	2	2
3	MIC AUDIO	6	6
4	MIC PTT*	3	3
5	SPKR AUDIO	7	7
6	IPCB	3	3

DC Power Connector J701 Signals:

This large 6-pin Molex connector is the main power feed for the control tray.

Pin	Signal Name	Src	Dst
1	A++ (AUX +13.8V)	2	2,7
2	KEYWAY (NO PIN)	---	---
3	OVERVOLTAGE ALARM*	3	4
4	BATTERY REVERT* (AC FAIL*)	3	4
5	GND B	1	1
6	NORMALIZED IF ENVELOPE (800/896)	8	8

Contact Information:

The author can be contacted at: his-callsign [ at ] comcast [ dot ] net.

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This article first compiled 13-Sep-2006.

Article text and hand-coded HTML © Copyright 2012 By Robert W. Meister WA1MIK.

This web page, this web site, the information presented in and on its pages and in these modifications and conversions is © Copyrighted 1995 and (date of last update) by Kevin Custer W3KKC and multiple originating authors. All Rights Reserved, including that of paper and web publication elsewhere.