Citizen Systems iDP3240 - Manual (Page 184)

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10) When more data is to be received from the printer, the host chooses one of
three status selections:
1. Setting HostBusy (nAutoFd) to Low and indicating that the host is ready to
receive.
2. Remaining in the Host Busy Data Available phase.
3. Performing Termination and returning to the Compatibility mode.
13.2.5 Device ID
The device ID is a character string that provides the ID, the type, and other
information regarding the printer connected to the interface. When the printer
receives a request for a device ID from the host, it replies with the following device
ID:
<00> H <2E> H
MFG : CBM ;
CMD : ESC / POS;
MDL : iDP3240 ;
CLS : PRINTER ;
The first two bytes of the device ID indicate the length of the entire device ID
(Including the first two bytes themselves). For a description of a request for a
device ID, refer to the “Negotiation” section earlier in the present Appendix.
When the host receives the device ID string of the length indicated by the first two
bytes, it must do so consecutively, without terminating the process until the entire
device ID is received. If the process is terminated halfway, the printer discards the
rest of the string; when the printer receives a new request for the device ID, it
sends the device ID beginning from the first character of the ID. After receiving the
ID of the length indicated by the first two bytes, the host must carry out the
termination even if the printer has data to send (Data Available). If the host does
not carry out Termination and tries to receive data, the printer sends the printer
status.
13.2.6 Termination
Termination is the process of returning to Compatibility mode from the Nibble or
Byte modes. When performing Termination, the host sets the signals as follows:
• IEEE 1284 Active (nSelectln): Low
• HostBusy (nAutoFd):
High (Event 22)
There are two methods of Termination:
(1) Termination through a handshake between the host and the printer.
(2) Immediate termination.