Pin assignments of Serial connecter

Pin number		Signal name		Signal description
1		HSKo		Handshake output. Vh=3.6V; Vl=-3.6V; Rl=450Ω
2		HSKi		Handshake input. Vh=0.2V; Vl=-0.2V; Rl=12KΩ
3		TxD-		Transit data (inverted), Vh=0.2V; Vl=-0.2V; Rl=12KΩ
4		GND		Signal ground
5		RxD-		Receive data (inverted), Vh=3.6V; Vl=-3.6V; Rl=450Ω
6		TxD+		Transit data, Vh=3.6V; Vl=-3.6V; Rl=450Ω
7		GPi		General-purpose input, Vh=0.2V; Vl=-0.2V; Rl=12KΩ
8		RxD+		Receive data, Vh=0.2V; Vl=-0.2V; Rl=12KΩ
9		PWR		+5V (modem port only)