I'm trying to hook up a Digital LQP02 serial daisywheel printer to a
Macintosh SE.

The pin-outs are:

LQP02 Digital Macintosh SE

Pin # Pin #
1 shield 1 HSKO
2 Tx data 2 HSKi
3 Rx data 3 TxD-
6 Data Set Ready 4 GND
7 Signal ground 5 RXD-
20 DTR 6 TxD+
7 GPi
8 RxD+

Which pins goes to which connection?

I understand that the grounds go together. What about the shield? Do I
really need it? The Tx goes to Rx, but the + and - TxD, RxD on the
Macintosh side was a little confusing.