AMT Datasouth XL 300 SERIES, Maintenance Manual

Page: 12 / 117

PIN
ASSIGNMENT
1. Chassis Ground
2. Serial Data Out
Asynchronous output data line
3. Serial Data In
Asynchronous input data line
7. Signal Ground
11. Data Terminal
Ready (DTR)
20. Data Terminal
Ready (DTR)
Indicates the printer is open for communication and can accept
or transmit data.
Table 1.1 Serial Interface Connector-Pin Assignment
1.15: CURRENT LOOP INTERFACE OPTION
A 20mA current loop interface is an available option. It functions in a manner identical to
the RS-232C, except that photo-isolated current loops are used instead of voltage levels.
Further, no equivalent of DTR restraint mode is available. The XON-XOFF mode of
handshaking is not affected, and may be used if desired.
The current loop receiver or transmitter may operate in either passive or active mode. The
standard factory setting is passive for both loops. When operating in passive mode, the
host system must supply the excitation or drive current. In active mode, the printer
provides the drive current, and the host acts as the passive device. If a loop is configured
for active operation, it should be noted that there no longer exists true photo-isolation
between the printer and host. This is because the printer's power supply is connected
directly to the output (or host) side of the photo-isolator.
Table 1.2 shows the jumper configuration required for active and passive mode of
operation.
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