Seagate ST39175FC, ST318275FC manual FC-SCA pin descriptions

Barracuda 18LP FC Installation Guide, Rev. A				25
Table 1: FC-SCA pin descriptions
	Pin/contact	Signal name	Signal type
1*	–EN bypass port A	TTL output
2*		12 Volts
3*		12 Volts
4*		12 Volts
5*		–Parallel ESI
6*		Ground[1]
7*		Active LED out	Open collector out
8*		Reserved
9*		Start_1	TTL input
10*		Start_2	TTL input
11*		–EN bypass port B	TTL output
12*		SEL_6	TTL input/output
13*		SEL_5	TTL input/output
14*		SEL_4	TTL input/output
15*		SEL_3	TTL input/output
16*		Fault LED out	Open collector out
17*		Reserved NC
18*		Reserved NC
19*		5 Volts
20*		5 Volts
21		12 Volts charge
22		Ground
23		Ground
24*		+Port A_in	Diff. PECL input pair
25*		–Port A_in