Black Box 5000 manual Appendix F Device Applications, Tandem

Appendix F: Device Applications

Appendix F: Device Applications

Extended WANG Support Feature (WANGX)

The extended WANG support feature (WANGX) provides special buffer control, flow control, and code levels for WANG 2200 computer systems support. These systems include 2200 UP, 2200 MUP, and 2200 LVP all using the 2236 MXD terminal processor and the 2236 DE interactive terminal as a standalone device or with any WANG printer slaved to it.

Communications are serial asynchronous, 11-bit code (1 start bit, 8 data bits, 1 odd parity bit, and 1 stop bit). The data rates normally used for WANGX channels are 300, 600, 1200, 2400, 4800, and 9600 bps.

To activate WANGX for a port, select WANGX buffer control and flow control using the Channel Characteristics Menu. A port using WANGX buffer and flow control will be transparent to the standard X-ON/X-OFF characters (DC1 and DC3).

The following points should be noted about ports using WANGX buffer and flow control:

•The View Channel Configuration display will indicate WANGX buffer and flow control for each port as applicable.

•Ports using WANGX buffer and flow control cannot use the Tandem Computer or Smooth Scroll features.

•Autobaud Rate Detection (ABR) (selected from the Data Rate Menu) does not operate on WANGX ports.

•WANGX ports should be configured in 9-level code, odd parity.

Tandem

Tandem non-stop computer data flow operation requires the use of a signal called T-Pause.

T-Pause is a control signal on pin 12 of the Tandem interface. This flow control signal is used as a function in response to remote printing terminal signals ready, abort, or temporary buffer full. The Multiserver unit will pass the T-Pause signal when yes is selected for Tandem in the Channel Features Menu (see Table 9-11).

Also, when Tandem computer support is enabled, DTR (pin 20) from the terminal is inverted and output as DSR (pin 6) to the host. However, the Multiserver unit provides normal DTR flow control response to the terminal.

Call your vendor if you need cables to support Tandem computers. They will need to be custom- made. If you wish to build your own cables, use the pin assignments in Figure B-13.

To enable Tandem computer support for a port, set the following configuration using the Channel Characteristics Menu and the Channel Features Menu (see Section 9.3, Asynchronous Channels):

•EIA Control Enable(d) at Host and Terminal ends

•Flow Control DTR at Terminal end

• Buffer Control	CTS at Host end
• Tandem	Yes at Host end

HP ENQ/ACK

The Multiserver can support Hewlett-Packard HP3000 View systems using type 26XX display stations operating under term type 10. To support them, the Multiserver unit emulates the HP ENQ/ACK pacing mechanism. Remote spooling for HP2631 and HP2635 printers (term type 19) is also supported.

The HP ENQ/ACK protocol is available to any port from the Channel Features Menu. When a Host end port (with HP ENQ/ACK option = yes) receives an ENQ poll following a block of data, it immediately emulates the remote terminal by responding with its own ACK. It then passes ENQ along to the terminal.

After outputting the data, the remote Multiserver unit buffers any additional data until the terminal sends an ACK or a 10-second timer expires. When the ACK is received, the remote Multiserver unit forwards data to the terminal (but does not forward ACK to the host).

To enable HP ENQ/ACK, set the following configuration using the Channel Characteristics Menu and the Channel Features Menu:

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