Impulse 3420 - Manual (Page 14)

Technical Description
Sealevel Systems COMM+8 Page 11
DB-78 Connector Pin Assignments (DB-78 Female)
Port # 1 2 3 4 5 6 7 8
TD 36 12 27 3 75 51 66 42
RD 37 11 28 2 76 50 67 41
RTS 17 31 8 22 56 70 47 61
CTS 16 32 7 23 55 71 46 62
DTR 35 13 26 4 74 52 65 43
DSR 18 30 9 21 57 69 48 60
DCD 38 10 29 1 77 49 68 40
RI 15 33 6 24 54 72 45 63
GND 34 14 25 5 73 53 64 44
Figure 11 - DB-78 Connector Pin Assignments
Technical Note: Please terminate any control signals that are not going to
be used. The most common way to do this is connect RTS to CTS and RI.
Also, connect DCD to DTR and DSR. Terminating these pins, if not used,
will help insure you get the best performance from your adapter.