Black Box COS-2, Manual

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HIGH SPEED COS-2
Table 4-1. Pinning, AT Computer to COS-2*
Computer COS
DB9 DB25
RD 2 ----------------------------------- 3 TD
TD 3 ----------------------------------- 2 RD
DTR† 4 ----------------------------------- 20 DTR†
SGND 5 ----------------------------------- 7 SGND
CTS† 8 ----------------------------------- 5 CTS†
Table 4-2. Pinning, PC/XT Computer or Serial Printer to COS-2‡
Computer COS-2
DB25 DB25
PGND 1 ----------------------------------- 1 PGND
TD 2 ----------------------------------- 2 RD
RD 3 ----------------------------------- 3 TD
RTS 4 ----------------------------------- 4 RTS
CTS† 5 ----------------------------------- 5 CTS†
DSR 6 ----------------------------------- 6 DSR
SGND 7 ----------------------------------- 7 SGND
RLSD [DCD] 8 ----------------------------------- 8 RLSD [DCD]
DTR† 20 ----------------------------------- 20 DTR†
*Our EVNBMC cable is pinned this way. It also carries the other pins supported by
the AT serial interface, but the High Speed COS-2 doesn’t support any of the other
pins except Pin 1, PGND, which is not required, and the pins for DSR and RLSD
(DCD), which the COS-2 ties high.
†The COS-2 takes DTR as input from any attached device and passes it through to
the device on the other side as CTS output.
‡Our ECM12C cable is pinnned this way. It also carries Pin 1, PGND (which the High
Speed COS-2 supports but doesn’t require), Pins 6 and 8, DSR and RLSD (DCD)
respectively (which the COS-2 ties high), and Pins 4 and 22, RTS and RI respectively
(which the COS-2 doesn’t support at all).