Hi,
I am designing alert sounder systems like Fire detection systems have To define the systems, the sounders are operating in the 24-30Vdc range. Also, I need to monitor operating conditions in the line of sounders. To do it so, I need to control 3 nodes of wire ( you can see below circuit ). Since I am limited in space in my PCB, I do not have space for relays,( and also hate clicking sounds of relays 
). Is there a unique IC to control these 3 channels?
thanx in advance
A MOSFET is the usual solution for DC switching.
Relay A can be replaced by a p-channel MOSFET.
Relay B and C are in a bridge configuration, you need an H-bridge for that - as used in e.g. motor controllers.
As you're using relays the current can't be high so most MOSFETs will happily do your switching.
(deleted)
Peter-CAD-HST:
I´m using 5 V 8-channel solid state relay high level trigger modul.
SSRs can't be used for DC.
Did you see the specs; "Load voltage range: 75 to 264VAC".
Leo..
