I know this was a US slash convention and was in the late 1990s or early 2000s. Links should take you to the full size version/.

edited:Possible candidates (1998-2000)
*Connexions - one fan remembers this as being the 1998 program*Eclecticon
*Friscon
*Mountain Media Con
*Revelcon
(no subject)
Date: 2015-02-19 06:57 am (UTC)(no subject)
Date: 2015-02-19 07:00 am (UTC)It was in a pile of convention program guides, but nothing seemed to match up.
(no subject)
Date: 2015-02-19 07:21 am (UTC)(no subject)
Date: 2015-02-19 10:53 am (UTC)Hotel chains that use lettering for Salon rooms include the Hilton, the Marriott, the Westin, Embassy Suites, and the Four Seasons. This is modern information, though. I couldn't match any of these with numbered meeting spaces (400, 500), but I suspect in the intervening 15+ years, some rooms have been renamed.
(no subject)
Date: 2015-02-19 03:26 pm (UTC)My personal guess is Connexions 1998 which was held on the east coast (Maryland) in April.
(no subject)
Date: 2015-02-19 04:43 pm (UTC)(no subject)
Date: 2015-02-19 05:48 pm (UTC)I know Connexions had single track programming for a while. Electicon was lighter on slash.....
(no subject)
Date: 2015-02-20 01:57 am (UTC)