talk mode

n.

A feature supported by Unix and some other OSes that allows two or more logged-in users to set up a real-time on-line conversation. It combines the immediacy of talking with all the precision (and verbosity) that written language entails. It is difficult to communicate inflection, though conventions have arisen for some of these (see the section on writing style in the Prependices for details).

Talk mode has a special set of jargon words, used to save typing, which are not used orally. Some of these are identical to (and probably derived from) Morse-code jargon used by ham-radio amateurs since the 1920s.

AFAIAC	as far as I am concerned
AFAIK	as far as I know
BCNU	be seeing you
BTW	by the way
BYE?	are you ready to unlink? (this is the standard way to end a talk-mode conversation; the other person types `BYE` to confirm, or else continues the conversation)
CUL	see you later
ENQ?	are you busy? (expects `ACK` or `NAK` in return)
FOO?	are you there? (often used on unexpected links, meaning also "Sorry if I butted in &ellipsis;" (linker) or "What's up?" (linkee))
FWIW	for what it's worth
FYI	for your information
FYA	for your amusement
GA	go ahead (used when two people have tried to type simultaneously; this cedes the right to type to the other)
GRMBL	grumble (expresses disquiet or disagreement)
HELLOP	hello? (an instance of the ‘-P’ convention)
IIRC	if I recall correctly
JAM	just a minute (equivalent to `SEC....` )
MIN	same as `JAM`
NIL	no (see NIL)
NP	no problem
O	over to you
OO	over and out
/	another form of "over to you" (from x/y as "x over y")
	lambda (used in discussing LISPy things)
OBTW	oh, by the way
OTOH	on the other hand
R U THERE?	are you there?
SEC	wait a second (sometimes written `SEC...` )
SYN	Are you busy? (expects ACK, SYN\|ACK, or RST in return; this is modeled on the TCP/IP handshake sequence)
T	yes (see the main entry for T)
TNX	thanks
TNX 1.0E6	thanks a million (humorous)
TNXE6	another form of "thanks a million"
TTBOMK	to the best of my knowledge
WRT	with regard to, or with respect to.
WTF	the universal interrogative particle; WTF knows what it means?
WTH	what the hell?
<double newline>	When the typing party has finished, he/she types two newlines to signal that he/she is done; this leaves a blank line between 'speeches' in the conversation, making it easier to reread the preceding text.
YHTBT	You Had To Be There. Used of a situation which loses significant meaning in the telling, usually because it's difficult to convey tone and timing.
<name>:	When three or more terminals are linked, it is conventional for each typist to prepend his/her login name or handle and a colon (or a hyphen) to each line to indicate who is typing (some conferencing facilities do this automatically). The login name is often shortened to a unique prefix (possibly a single letter) during a very long conversation.
///	A giggle or chuckle. On a MUD, this usually means 'earthquake fault'.
<g>	grin
<gd&r>	grinning, ducking, and running
BBL	be back later
BRB	be right back
HHOJ	ha ha only joking
HHOK	ha ha only kidding
HHOS	ha ha only serious
IMHO	in my humble opinion (see IMHO)
LOL	laughing out loud
NHOH	Never Heard of Him/Her (often used in initgame)
ROTF	rolling on the floor
ROTFL	rolling on the floor laughing
AFK	away from keyboard
b4	before
CU l8tr	see you later
MORF	male or female?
TTFN	ta-ta for now
TTYL	talk to you later
OIC	oh, I see
rehi	hello again

Most of these are not used at universities or in the Unix world, though ROTF and TTFN have gained some currency there and IMHO is common; conversely, most of the people who know these are unfamiliar with FOO?, BCNU, HELLOP, NIL, and T.

The MUD community uses a mixture of Usenet/Internet emoticons, a few of the more natural of the old-style talk-mode abbrevs, and some of the ‘social’ list above; specifically, MUD respondents report use of BBL, BRB, LOL, b4, BTW, WTF, TTFN, and WTH. The use of rehi is also common; in fact, mudders are fond of re- compounds and will frequently rehug or rebonk (see bonk/oif) people. The word re by itself is taken as ‘regreet’. In general, though, MUDders express a preference for typing things out in full rather than using abbreviations; this may be due to the relative youth of the MUD cultures, which tend to include many touch typists and to assume high-speed links. The following uses specific to MUDs are reported:

CU l8er	see you later (mutant of `CU l8tr`)
FOAD	fuck off and die (use of this is generally OTT)
OTT	over the top (excessive, uncalled for)
ppl	abbrev for "people"
THX	thanks (mutant of `TNX`; clearly this comes in batches of 1138 (the Lucasian K)).
UOK?	are you OK?

Some B1FFisms (notably the variant spelling d00d) appear to be passing into wider use among some subgroups of MUDders.

One final note on talk mode style: neophytes, when in talk mode, often seem to think they must produce letter-perfect prose because they are typing rather than speaking. This is not the best approach. It can be very frustrating to wait while your partner pauses to think of a word, or repeatedly makes the same spelling error and backs up to fix it. It is usually best just to leave typographical errors behind and plunge forward, unless severe confusion may result; in that case it is often fastest just to type "xxx" and start over from before the mistake.