Intermec VT220/ANSI, Programmer'S Reference Manual

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SECTION 8
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Programming
8-38 VT220/ANSI Terminal Emulation Programmer’s Reference Guide
DCS indicates the beginning of a device control string.
DCS is an 8-bit C1 character (90 hexadecimal ). You can
use ESC P (1B and 50 hexadecimals) for a 7-bit environ-
ment.
Pc is the clear parameter that selects how to clear key de-
finitions. The following chart summarizes Pc values and
meanings.
Pc Meaning
0 (default) or none Clear all keys before loading new values.
1 Clear one key at a time, before loading a
new value.
When Pc is 1, the wireless station only clears the keys you
are loading. By using a Pc value of 1, you can redefine
some keys without redefining them all.
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NOTE: There are 256 bytes of memory for all UDKs. A key definition can
only use the number of bytes available when that key is loaded.
If Pc is 1, a key load may fail because no memory space is
available. The reason for this is, with Pc set to 1, keys are
cleared and loaded sequentially. If the new definition for a
key is larger than the old one you may exceed the 256-byte
limit.
For example, suppose F6 contains 120 bytes, F7 contains
110 bytes, and F8 contains 20 bytes. You try to load F8
with 40 bytes, F6 with 1 byte, and F7 with 1 byte, in that
order. This works if all keys are cleared first (Pc is 0), but
not if keys are cleared one at a time (Pc is 1). When you try
to load F8 with 40 bytes, the load fails because only 26
bytes are free at that time. (256 maximum -- 120 in F6 --
110 in F7 = 26.)
Pl is the lock parameter. Pl determines whether the key
definitions are locked or unlocked after you load them. The
following chart summarizes Pl values and meanings.