saam@bigblackbox:/tmp$ jack_control dps device hw:USB dps rate 48000 dps period 1024 dps nperiods 3 start
--- driver param set "device" -> "hw:USB"
--- driver param set "rate" -> "48000"
--- driver param set "period" -> "1024"
--- driver param set "nperiods" -> "3"
--- start
DBus exception: org.jackaudio.Error.Generic: Failed to open server
saam@bigblackbox:/tmp$