	Computer Automation Technology Fort Lauderdale, Florida	CAT Note 21
	Release Date: March 18, 2008
	CAT-250 to M/A COM Master III

This CAT Note describes the wiring between a (GE) M/A-COM MASTER-III and the CAT-250 Controller. Connection is made between the CAT-250 and the 2/4-wire 600 ohm balance line ports that would normally be used to connect a remote console via D.C. or tone remote control over telephone lines. The MASTER-III Control Shelf Personality was setup as 4-wire D.C. Remote Control. The digital pots were optimized for audio Input/Output levels of -10 dBm at the 4-wire line terminals with full system deviation. Please note that User Output #1 was configured in this example to control the MASTER-III CG Monitor (PL Disable) function from the CAT-250 controller but any of the available User Outputs may be selected.

M/A-COM MASTR-III		CAT-250 Repeater Controller
P2-1	A+	J3-CNTR	+ 12 VDC INPUT
P2-2	DGND	J3-RING	GROUND
P2-14	RMT REPEATER PTT IN	J2-10	PTT #1
P3-5	COR	J2-6	COR #1
P3-8	CG MON	J2-14	USER OUTPUT #1
P3-16	RUS	J2-4	CTCSS #1
J109-2	DUPLEX AUDIO (+)	J2-11	TX AUDIO #1
J109-5	DUPLEX AUDIO (-)	J2-17	GROUND
J109-3	LINE AUDIO (+)	J2-13	RX AUDIO #1
J109-4	LINE AUDIO (-)	J2-18	GROUND

Install a 680 ohm resistor across RX AUDIO #1 to ground as this is needed to provide a proper termination for the Master-III Line Output. Remove the jumper block from J8 of the CAT-250 to option the input stage for de-emphasized audio as supplied by the Mastr-III. Strap J-104 (2-3) and J-105 (2-3) on the Mastr-III T/R Board.

Channel Data

Ch	1	Rpt	N
Tx Freq	XXX.XXXX	Rf Sim	No
Tx Cg	XXX.X	CCT	0
BW	25	DODT	0.0
Rx Freq	XXX.XXXX	Tx Pot	250
Rx Cg	XXX.X	Cg Pot	95
Cg Lvl	Low	Pa Pwr	95
Ste	Y

Control Shelf Options

Battery Alarm	Disabled	Voting System	Disabled
Logic Standby	Disabled	Control Line	4 Wire
Intercom	No	Sidetone	No
Reference Freq	Internal	Rx Option	None
Circulator	Disabled	DTMF	Disabled
Synth. Part No	New	Digital Pager	Disabled

Morse Code Options

Mores Code	Disabled	Wait	5
Ch	1	Tx Required	Yes
MCID Enabled	Yes	ID With Keys	No
ID Text	EGEMASTER	Tx Pot	No
Interval	30	ID On Ch Change	No

PTT Options

Repeat	CCT, DODT, CG ENCODE
Remote	CG ENCODE
Local	CCT, CG ENCODE
External	CG ENCODE
Morse Code ID	None

Potentiometer Settings

Line Out	14	Dsp Line In	48
Repeater Gain	816	Dsp Compressor	1190
Line In	0	Dsp Comp Level	3157
Dsp Line Cancel	0	Squelch Pot	Manual

Information courtesy of WA8WG

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Computer Automation Technology, Inc.
4631 N.W. 31st Avenue, Suite 142
Fort Lauderdale, Florida 33309