Avery Berkel CX20 SERIES, Service Manual

Page: 220 / 353

22 — Communications Controller
22–7 CX20/CX30/CX34 Service Manual
Table 22.1 Comms PCB – Main Components
Batteries
BAT1 For RAM back–up.
Light Emitting Diodes (LEDs)
D17 The LED flashes to indicate software error or failure. The
number of flashes represent an error number (printed on TEST
REPORT instead of comms controller software number) which
represents a software error. See Section 10.
Integrated Circuits
IC1 Microprocessor
IC16 DUART
IC14 EPROM: the following types are available (selectable by setting
Links 6 and 7 – refer to Figure 22.3): 27512 (64k x 8); 27C101
(128k x 8); 27C020 (256k x 8); and 27C401 (512k x 8)
IC31 TO
IC38
INCLUSIVE
RAM: battery–backed static, maximum capacity 1Mb (8 x 128
Kbyte SMT devices)
Links
LK1 Selects either 20mA current loop host/master or RS232
channel (see Figure 22.3)
LK6
EPROM i l ti ( Fi 22 3)
LK7
EPROM program memory size selection (see Figure 22.3)
Electrical Connections
PL1 16–way right–angle IDC header. Provides the power supplies
and the ISC communications to the comms PCB.
PL5 10–way IDC header
Test Points
TP1 Host channel receive signal.
TP2 Host channel transmit signal.
TP3 ISC channel receive signal.
TP4 ISC channel transmit signal.
TP13 TO
TP16
INCLUSIVE
Not used.
Switches
SW1 Not used (see Figure 22.4)
SW2 Battery ON or OFF (see Figure 22.4)
SW3 Selects main or back–up controller (see Figure 22.4)