DEC DECrepeater 90T, Owner'S Manual

Page: 56 / 62

C
Management Details
Designating a Hub Manager
The protocol used on the DEChub management bus allows for only a
single manager unit to access the management bus. When a DECbridge
90 is first powered on or reset, it waits 60 seconds to be sure that there
is no other manager unit in use in the hub, before it claims itself as the
designated hub manager. For this reason, you will not be able to remotely
manage the DECrepeater 90 units for 60 seconds following the power-
on or reset of the DECbridge 90. This restriction does not apply to the
repeaters themselves. A repeater inserted into the hub is immediately
manageable by whatever unit is currently the designated hub manager.
If you receive the message "The DECbridge 90 is not the designated hub
manager.", and the DECbridge 90 has been running for more than 60
seconds, there is something wrong.
If using two hubs, be sure the MMJ cable is wired correctly, and it not
shorted or broken.
If using only one hub, the MMJ connector should be disconnected.
Only one DECbridge 90 unit is allowed in the Hub. If more than one
is inserted, only one of them will be able to manage the repeaters.
The other unit will issue this message.
If for some reason you do NOT wish a specific DECbridge 90 unit to be the
designated hub manager, you can disable the hub management features
with the command DEFINE BRIDGE HUB_MANAGEMENT DISABLE.
Once the DECbridge 90 has become the designated hub manager, it can
do SET or SHOW REPEATER and SET or SHOW PORT commands
without restriction. There is, however, an additional delay before the
SHOW ADDRESS command will have complete information. DEFINE
commands do not take effect until the next SET ALL or RESET of the
DECbridge 90. To have the command take effect immediately, you must
also issue the corresponding SET command.
48 Digital Internal User Only