BOS, Appendix F - Multiplexor Panel

Branch Office System
Appendix F - Multiplexor Panel

The multiplexor panel is installed in the lowest ISA slot position of the BOS backplane. It distributes speaker signals and supervisory I/O control signals to BC processors within the Cubix Branch Office Desktop System. Access to mouse I/O configuration switches for QL cards installed in channels 4 and 5 is provided. One option switch is provided to allow booting from floppy drive on channel 1.The panel multiplexes the signals for a single monitor, keyboard, mouse, reset switch, floppy diskette drive(s), and status LEDs for each BC processor in the system. The panel also provides multiplexed "STATUS LED" outputs for Cubix multiport peripheral PC cards and buffered drives for status LEDs from the Cubix IES module.

Multiplexor DescriptionPower Distribution+5vdc and -5vdc are input from the ISA card edge connector to operate all functions on the multiplexor. CB1, an automatic resetting, 2A solid state circuit breaker provides +5vdc power protection to the external keyboard, mouse connectors on the end bracket, and the front speaker connector.

Speaker Connections The BC Series processors installed in the BOS system share a common speaker output. An 8 ohm permanent magnet speaker is attached to pins 1 and 4 of J31. The BC Series processor's speaker outputs are attached to the multiplexor on J11, J6, and J1 for BC channels 1 through 3 respectively and pin 11 of J26, J19, J14, J9, and J4 for BC channels 1 through 5 respectively.

Supervisory (IES) Support (Optional) If the optional Cubix IES module is installed in the BOS system, there are two short cables required to interface the IES module to the multiplexor. J20, a 10 pin ribbon header, is connected to a 10 pin header directly above it on the IES module providing connections for the front panel IES LED display and circuit breaker status input. J21, a 26 pin ribbon header, is connected to a 26 pin ribbon header directly above it on the IES module. This provides connections for BC status and BC reset control for each BC processor in the Branch Office System.

BC Processor Reset The multiplexor provides the ability to manually reset the BC Series processors installed in the BOS. The recessed front panel reset button is connected to the BC processor selected by the multiplexor. The demultiplexed reset signal is connected to the BC processors via pin 5 of J11, J6, and J1 for channels 1 through 3, and via pin 12 of J26, J19, J14, J9, and J4 for BC channels 1 through 5 respectively.

Video/Keyboard/Mouse Multiplexor A single VGA monitor, PS/2 keyboard, and PS/2 mouse may be shared by all the BC processors installed in the BOS. The I/O connections are located on the end bracket at the rear of the subsystem. Observing the rear of the unit, the keyboard is connected to the 6 pin minidin connector J34 on the left, the PS/2 mouse is connected to the 6 pin minidin connector J30 on the right of the end bracket, and the VGA monitor is connected to the DB HD15 connector, J32, in the center of the end bracket.

Each BC Series processor installed in groups 1 through 5 is equipped with a 26 pin signal interface which is connected to the multiplexor via a 26 pin ribbon cable. Multiplexor connectors J20, J19, J14, J9, and J4 interface the video, keyboard, and mouse signals from BC processor channel 1 through 5 respectively.

BC Status LED Multiplexor A group of six green LED status indicators, located on the front panel, are shared among all the BC Series processors installed in the BOS system.

These LEDs, which are enabled concurrently with the selected BC processor, provide a visual indication of the rate of activity and status for the following signals: >PRE> 1. BC LAN activity 2. BC IDE disk activity 3. BC COM1 TXD, serial transmit activity 4. BC COM1 RXD, serial receive data activity 5. BC COM1 DTR, terminal ready signal from connected peripheral 6. BC COM1 DCD, carrier detect signal from connected peripheral These status signals are also interfaced from the BC processors to the multiplexor via 26 pin ribbon connectors J26, J19, J14, J9, and J4 for BC channels 1 through 5 respectively.

Multiport Controller LED Status Multiplexor A group of eight green LED indicators are shared among all Cubix multiport controller serial ports installed in the BOS system. These LEDs, which are selected with the port group and port front panel selectors, provide a useful visual indication of the status and rates of activity for the following signals:

1. COM PORT TXD, transmit data
2. COM PORT RXD, receive data
3. COM PORT RTS, request to send
4. COM PORT CTS, clear to send data
5. COM PORT DSR, data set ready
6. COM PORT DTR, data terminal ready
7. COM PORT CARRIER, data carrier detected
8. COM PORT RING, ring signal detected

These status signals are interfaced from the Cubix multiport controllers to the multiplexor via a single 16 pin ribbon cable which is daisy chained between all multiport boards and interfaced on the multiplexor at ribbon header J23.

Operation The multiplexor in the BOS system is always "ON" and connected to a BC processor input channel, "port group" input channel, and "port" input channel. The keylock switch provided on the front panel "locks" the multiplexor in its selected channel and inhibits operation of the mouse, keyboard, and floppy disk when locked.

During the time that the keylock switch is in the unlocked position, the multiplexor is fully operational.To connect the monitor, keyboard, mouse, reset pushbutton and floppy drive to another BC processor, follow these steps:

1. Verify the keylock switch is in the "unlocked" position.

2. Press the front panel PROCESSOR switch to advance the multiplexor to the next BC processor channel.

3. Step 2 may be repeated up to four more times to sequentially select all available BC processor channels.

Floppy Diskette Multiplexor

The BOS system contains either a single 3.5" TH floppy drive, addressed as "DRIVE A:", or a dual 3.5"/5.25" HH floppy drive with the 3.5" drive addressed as "DRIVE B:" and the 5.25" drive addressed as "DRIVE A:". The installed drive is shared by all BC processors in the system.

+5vdc and +12vdc power for either drive is provided on the power supply assembly at J8. The 34 pin data cable connects to the multiplexor floppy data output connector J29. Each BC Series processor must be connected to the multiplexor via 34 pin ribbon cable at connectors J24, J18, J13, J8, and J3 for BC processor channels 1 through 5 respectively.

The multiplexor presents the "disk change" signal to the BC processor when connecting to the processor. This forces the processor to re-read the floppy directory when accessing the disk the first time after connecting. Correct directory information is ensured.

* Do not change BC processor channels while any floppy disk operations are underway. Data integrity can not be guaranteed.P

Port Group and Port

The PORT GROUP and PORT displays apply to the selected port on the selected multiport adapter. In the BOS system, the front panel keylock switch must be in the unlocked position to allow any selection changes. To operate:

1. Verify the front panel keylock switch is in the "unlocked" position.

2. To advance between ports in the same port group (or on the same multiport adapter), press the PORT pushbutton on the front panel. Pressing this switch eight times advances trough all available ports in a single port group. Note that these ports are numbered 0 through 7.

3. To advance between port groups, press the PORT GROUP pushbutton on the front panel. The status of the same port in successive port groups will be displayed. Pressing this switch five times advances through all available port groups. A group of ports is eight ports implemented on a single multiport adapter. Note that the port groups are numbered 0 through 4.

The channels supported by the BOS multiplexor are:

1. 5 processor channels displayed as channels 1 through 5.

2. 8 port channels displayed as channels 0 through 7.

3. 5 port group channels displayed as channels 0 through 4.

QL Series Mouse Support

The multiplexor supports an adjustable mouse I/O configuration when interfacing to installed QL Series Cubix processors.

QL processor interfaces are provided on processor channels 4 and 5. The channel 4 interface consists of one 14 pin video, keyboard, and mouse header (J25) and one 3 pin locking Molex header (J22) for mouse only. The channel 5 interface consists of J17 (a 14 pin header) and J15 (a 3 pin locking Molex header). When channel 5 is used to interface to a QL 4001 processor, dip switches S2-1 and S2-2 must be in the OFF position. When channels 4 and/or 5 are used to interface a QL 3002 Series processor ports A and/or B to the multiplexor, then dip switches S2-1, S2-2, S3-1, and S3-2 must be in the OFF (default) position.

If a QL 3222 processor ports A and B are interfaced to the multiplexor, then S2-1, S2-2, S3-1, and S3-2 must be switched to the ON position to enable the mouse interfaces in J25 and J17 pins 10 and 12. This page intentionally left blank.

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Multiplexor Panel