PIN	Function	Direction	Notes and limitations
1	CTCSS logic output (active low) or CTCSS disable input	In/Out	SJ1 - SJ2 sets function - see instructions
2	Receive audio input - to high pass filter	In	Operates only in RX mode - SJ5 connects pins 2 and 3 together
3	Discriminator audio input	In	Connects also to pin 16
4	CTCSS tone output	Out	Operates only in TX mode
5	Receive audio output - from HP filter	Out	Operates only in RX mode
6	Transmit audio output - from HP filter	Out	Operates only in TX mode
7	Spare - can be routed anywhere desired	In/Out	Can connect to A - F outputs or elsewhere
8	Transmit audio input - to HP filter	In	Operates only in TX mode
9	RX - TX mode switch	In	Ground for TX mode (encode only)
10	CTCSS logic output (active high)	Out	Current limited - includes a pull-down
11	COS output (active high)	Out	Current limited - includes a pull-down - "AND" Output when SJ2 in place (active high)
12	Spare - can be routed anywhere desired	In/Out	Can connect to A - F outputs or elsewhere
13	Power supply positive (+12 to +16 VDC)	In	12 - 16 VDC typical, up to 24 VDC maximum
14	PTL (push to listen)	In	See FX465 data sheet for operation
15	RUS (active low)	Out	Original logic out of MICOR squelch chip
16	Discriminator audio output	Out	Connects to pin 3
17	COS output (active low)	Out	"AND" output when SJ2 in place (active low)
18	Ground
19	Ground
20	Ground
21	Ground
22	Ground
23	Ground
24	Ground
25	Spare - can be routed anywhere desired	In/Out	Can connect to A - F outputs or elsewhere
NOTE:	Use outputs A - F only when primary logic outputs above cannot be used!	NOTE:	These can be tied to "Spare" pins 7, 12, and 25.
A	Alternate Open Collector COS output (active low) Use of "F" is preferred	Out	Use position "F" because of less junction "depth"
B	Alternate Open Collector COS output (active low) Use of "F" is preferred	Out	Use position "F" because LED bias/operation can be affected
C	Open Collector COS output (active high)	Out	Preferred Open Collector output for active high COS
D	Open Collector CTCSS output (active high)	Out	Preferred Open Collector output for active high CTCSS
E	Open Collector CTCSS output (active low)	Out	Preferred Open Collector output for active low CTCSS
F	Open Collector COS output (active low)	Out	Preferred Open Collector output for active low COS