Zilog Z80195 - Manual (Page 12)

Z80185/195 D EVELOPMENT K IT
U SER ' S M ANUAL
2-4 UM951800100
Z ILOG
SETTING UP THE HARDWARE (Continued)
Function Jumper Connections
LocalTalk/AppleTalk connector J15-1 to J15-2
from J16
J10 or J11 J15-2 to J15-3
Note: This board has no provision for “clock” or “handshake” input or output on the J16 LocalTalk/
AppleTalk connector.
RS-232 or RS-422/485 for ASCI0 and ESCC Channel
Pins 4-7 of J15 determine whether the board uses RS-232 “unbalanced” signaling, or RS-422/485
“balanced” or “differential” signaling on the DB-25 connectors for ASCI0 and the ESCC channel. RS-
232 is more common but is limited up to 115,200 bits/second, and cables up to about 25 feet long.
RS-422/485 can handle higher serial rates and longer cables.
Function Jumper Connections
RS-232 for ESCC on J10 or J11 Leave open J15-5.
RS-422/485 on J10 or J11 Jumper J15-4 to J15-4.
RS-232 for ASCI0 on J12 or J13 Leave open J15-7 open.
RS-422/485 on J12 or J13 Jumper J15-7 to J15-6 to use.
DCE or DTE Pinning for ASCI0 and the ESCC Channel
The RS-232 and EIA-570 standards define connection between a piece of Data Terminal Equipment
(DTE) such as a dumb terminal or a computer system, and a piece of Data Communications
Equipment (DCE) such as a modem. The 185/195 board can act as either a DTE or DCE device. For
ASCI0 and the ESCC channel this choice depends on which connector you use.
Male DB-25 J10. Provides DTE pinning for the ESCC channel, and is suitable for connecting to a
modem via a “straight-through” cable, or to a computer via a “null modem” cable.
Female DB-25 J11. Provides DCE pinning for the ESCC channel, and is suitable for connecting to
a computer via a straight through cable, or to a modem via a null modem cable.
Male DB-25 J12. Provides DTE pinning for ASCI0, and is suitable for connecting to a modem via a
straight-through cable, or to a computer via a null modem cable.
Female DB-25 J13. Provides DCE pinning for ASCI0, and is suitable for connecting to a computer
via a straight-through cable, or to a modem via a null modem” cable.
Note: Signal names, which are shown on the board schematic in this manual with an over bar to
indicate an active low signal, are shown in the following sections with a slash before the name, for
example “/DSR”.