Citizen Systems Citizen CLP 8301 CLP-8301 User Manual
Page 73
Chapter 9 Specifications
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59
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DTR protocol
DTR signal “Ready (High)” level requirements:
The following must be satisfied:
•
Printer is on line.
•
Receive buffer has more than 128 bytes available.
Note: When receive buffer has less than 128 bytes available, DTR signal becomes “Busy
(Low)” level and this “Busy (Low) level is kept until receive buffer has at least 1K bytes
available.
DTR signal “Busy (Low)” level requirements:
The following must be satisfied:
•
Printer is in error.
•
Printer is in paused state.
•
Receive buffer has less than 128 bytes available.
Pin assignment
Pin No.
Signal
Input/Output
Description
1
FG
Output
Frame ground
7
SGND
Output
Signal ground
2
TXD
Output
Signal to transmit data
3
RXD
Input
Signal to receive data
4
RTS
Output
Transmission request signal. Pull up to +12V with
3.3Kohm
6
DSR
Input
Signal active when host computer ready to interface with
printer
20
DTR
Output
Signal active when printer ready to interface with host
computer
25
VCC
Output
(Factory use)