Black Box A/S-4 manual Batch Operation

CHAPTER 8: Batch Operation

When sending data to the printer each character is inspected and then sent if needed. A column count is kept to determine the position of the printer’s print head which is compared to the selected column width of the paper. If a space character is found, it is not sent right away to the printer. The following characters are checked and if no other character other than a space is present in the line, a CR LF or CR LF LF (Double spacing) is sent to the printer disregarding the received spaces.

The SNA host can send transparent data to the printer. Most of the time this EBCDIC data is converted into ASCII because transparence is generated by the application (e.g. JES, POWER) which looks for a character less than an EBCDIC space (x’40’) in value, if this character is found, the print line is sent in transparent form. Usually the character causing this is a null (X’00’) inserted in a JOB name or ROOM number because no value was assigned. If the actual SNA data received from the host needs to be printed, the first two data characters must be a transparent indicator (TRN X ‘35’) followed by the number of transparent characters in hexadecimal. Example message received from SNA host:

TRN # TRN # data —> 1st TRN # generated by JES 2nd TRN # generated by program The printer can be connected to the A/S-4 in many ways as mentioned below:

1.Printer directly connected to the terminal port with a single cable. In this configuration no VDU is present. The host must do an Auto-BIND to connect the A/S-4 to he application (e.g. JES2, CICS) or use the Auto Logon function of the unit. With a single device, only one LU is needed but both may be used. Normally the VDU LU is the LU used when running with a single LU. The host must start the print job since no VDU is present. Hardware throttle (must have CTS before sending data) or software throttle (XON/OFF protocol) may be used to control the rate of data going to the printer.

2.Printer attached to a VDU’s auxiliary/printer port where the VDU is directly connected to the terminal port of the A/S-4. This mode of operation allows the VDU to run at a faster baud rate than it’s attached printer. Having two LUs active, one for inbound (to host) data and an outbound (from host) LU will increase the speed of the printer and also allow the VDU to start or stop jobs, interrupt the printer or allow a card device to send a job in to the host while a job is being printed. Software or hardware throttle is supported.

3.Printer attached with the special “Y” VDU/Printer cable. The VDU and printer must run at the same baud rate in this setup and hardware throttle is the only way to control the flow of data to the printer (XON/OFF not supported). When using the “Y” cable, the VDU will be able to receive data while the printer is off-line, replacing paper or throttling. This configuration is very similar to item 2 with two LUs active which allows the VDU to control the printer. In this mode the VDU (PC or computer) can go off-line and run applications while the printer is receiving data from the SNA host, as long as the VDU supplies Data Terminal Ready (DTR) pin 20 to the A/S-4.

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