These things aren't bound to these keys for a reason, just the first letter to come to mind

Supply Depot Alias

alias +depot "supplydepot;wfteamplay radio/engineer/cs_depoten.wav"
alias -depot "supplydepot;wfteamplay radio/engineer/cs_depotdis.wav"
bind d +depot

Sentry Gun Alias

alias +sentry "sentry build;wfteamplay radio/engineer/cs_sentry.wav"
alias -sentry "sentry remove;wfteamplay radio/engineer/cs_sentrydis.wav"
bind s +sentry

Alarm

alias +alarm "alarm on"
alias -alarm "alarm off"
bind a alarm