NCR 7156, Owner'S Manual, Page: 116 / 138

Chapter 6: Commands 7156 Owner’s Guide
September 1997 110
Maintaining the Exception Table
Present contents of the exception table can be examined using the read NVRAM command:
0x1B 0x6A k
which reads and returns word k in NVRAM. When the exception table is full, a new entry
can replace an older, less frequently used entry, by merely rewriting the words for that
table entry.
General Slip Handling
The Select Sensors to Stop Printing command (Hex 1B 63 34 n—ASCII ESC c 4 n)
determines which sensor stops printing on the selected station. Usually, an application
would send n = 60 (bits 4 and 5 on) with this command in order to stop the printer when
either slip sensor is uncovered.
However, in actual use this does not work well for printing checks, when the leading edge
sensor (inside the printer) must be uncovered to print close to the top edge of the paper.
It also doesn’t work well with long forms which can’t be fed back out completely past the
leading edge sensor without the form falling on the floor when the trailing edge sensor (at
the front of the printer) becomes uncovered.
In order to correct this problem and with the slip sensors, use the Transmit Printer Status
command (1B 76—ESC v) for each line. This will ensure that checks are printed to the top
edge of the paper and that the printer will not go into a waiting state when printing long
forms.
Use one of the following two methods for doing this.
First Method
This method keeps control in the application.
1. Send the Select Slip Station command (1C).
2. Send the Transmit Printer Status command (1B 76) repeatedly until the response
indicates that both slip sensors are covered.
You can stop the transaction whenever you want to as control is with the application.
3. Receive the response
If Bit 5 = 0 (leading edge uncovered) or Bit 6 = 0 (trailing edge uncovered), go back to
step 2.
4. Send the Reverse Feed n Lines command (1D 14 n) with n = 03.
This uncovers the leading edge sensor.
5. Send the data for the print line until finished.
You can continue to watch the slip sensors between print lines using the Transmit Printer
Status command (1B 76).
When a slip is inserted to the slip stop, the leading edge is about 0.6 inches from the print
line. You can reverse feed the paper about four lines (depending on your line spacing) to
get to the top of the paper.