2.2 The IBM 7171 ASCII Device Attachment Control Unit - Index of

This devices' address may not be enabled at the host. Inbound interrupts will beswallowed by the host without any response.• Enable the device address.Possibly the channel cables are incorrectly hooked up, faulty, or not attached.If no channel cables are attached to the 7171, it will not ready after powering up.There is a READY light on the front of the box to check if this is the case.• Test the channel cables to see if they are faulty.C-3: Interface Control Check, 'GOT STATUS OF WRONG DEVICE ... 'This is a user error in the UCW definitions of the channel. This 48/64 port 7171has a single UCW defined instead of one for each 32 ports. The 7171 is programmedto treat each 32 port group independently. It may present status asynchronouslyon one sub channel while within a CCW chain on the other subchannel.This is justification for an Interface Control Check in a single UCW environment.• A UCW redefinition is required. Reference the 7171 Description and PlanningGuide section 'Connection to the Host' for assistance.C -4: 7171 locks up on first readying terminal with first write commandThe channel UCW definition for the 7171 addresses is Selector, or BMPX with theSelector option. Selector channels remain dedicated to the control unit from initialstatus to ending status for a command. A BMPX channel is dedicated from initialstatus till channel end status. Then device end status is presented asynchronously.The 7171 is internally programmed to always work with a BMPX channel. The7171 will lock a selector channel when it attempts to present status asynchronously.• Redefine the UCW to be a Blocked Multiplexor without the Selector option. Ifassistance is required, reference 8.1.1, "Assistance for ProblemDetermination. "C-5: READY drops when 7171 switched onlineThe channel cables are incorrectly hooked up, faulty, or not attached.If no channel cables are attached to the 7171, it will not ready after powering up.There is a READY light on the front of the box to check if this is the case.• Test the channel cables to see if they are faulty.C-6: Operational checks for a 7171 deviceThe Operating System (SCP) sysgen is incorrect. An invalid device type exists inthe 7171 portion of the host sysgen definition. The address associated with theerror message is the device type in error in the sysgen.Either the SCP sysgen should be redone, or that 7171 address should not be used.8-26 IBM 7171 Reference Manual and Programming Guide