User`s manual

SIERRA VIDEO SYSTEMS
34
command, that will not permit the device to reroute locked outputs (but it can use the
administrator password to unlock locked outputs using the “B” command).
Output lockouts apply on all levels. On virtual-mapped routers, a level may be left out of a lockout
by making sure the level is unmapped for the destination being locked.
As with all router configuration parameters, the output lockout data is stored in non-volatile
storage and thus is retained across router power-ups. When a router is first initialized at the
factory, all outputs are set to be unlocked.
This command provides the same functionality as the “G OUTPUT_LOCK” command. This
command, which was added at router software version V5.06, is preferred over that command.
Note that the output lock version number is not present in this command. Since output lock status
changes frequently, it is not really useful to cache output lock status for outputs, so the output
lock version number is not really useful.
For example, to request whether or not output 21 is locked:
** B21,0,0 !!
The response might be:
** B21,0,0 OK !!
indicating that output 21 is NOT locked. Or, the response might be:
** B21,6741,1 OK !!
indicating that output 21 is locked with password 6741. To clear this lockout:
** B21,6741,0 !!
To lock output 96 using password 439:
** B96,439,1 !!
If successful, the response would be:
** B96,439,1 OK !!
If output 122 becomes locked using password 235, the following change report would be sent by
the router:
** B122,235,1 !!
“F”: Field Delay
The command "F" is used to specify the delay between the time a crosspoint change request is
received by the router and the time the crosspoint switch actually occurs. It must be followed by a
number giving the number of video fields of delay desired. If the number is smaller than the
smallest delay that the router can handle, the smallest delay is used instead. If it is larger than the
largest delay the router can handle, the largest delay is used instead. Note that this command
does not cause a delay in command processing, as the “D” command does.
To understand this command more fully, consider the way that router software will typically
handle a crosspoint command. The last character of the command string, the final “!”
(exclamation) character, is received somewhere in a particular video field, call it video field 7. The
router parses the command string and, for each crosspoint it contains, it puts the crosspoint in a
buffer that is marked to be delivered to the crosspoint hardware on a particular video field.
Suppose that previously, an “F5” command has been received. Then crosspoint commands
whose final “!” command string character was received on video field 7 would be placed in a
buffer that is marked to be delivered to the crosspoint hardware at video field 13 (7+5+1=13).
To understand the reason for adding 1 in the previous sum, consider an “F0” command: it would
ask for output at the very next video field, field 8 in our case. So, it is necessary to add the “F”
argument plus 1 to the field number on which the crosspoint command is received to get the field
number at which the crosspoint will be output.
A typical router will have a minimum delay that is between 1 and 2 fields. Suppose a crosspoint
command is received just before a vertical field mark. The software may be able to prepare the
crosspoint data and send it to the hardware when that vertical field mark occurs, but the hardware