I'm trying to learn a little more about the Toshiba Telecom line of products and I've seen both CTX and DK series of phone systems still in service in a lot of locations and I'm wondering what separates the 2 feature wise? Take the CTX series of phone systems for example regarding multiple call groups, the DK programming manual doesn't seem to have such a feature available? With CO line appearances on the CTX you can either set it for immediate ring, Delayed ringing, or no ringing but Program 39 in the DK doesn't seem to have that feature? Does department ringing exist in the DK system? Also does the DK system allow all phones to have CO line indicators but only certain phones ring for that line? The DK system seems to allow groups access codes for CO lines or a general dial 9 group but can that be changed to 8 or 7 like the CTX system? What other features does the CTX/CIX have over the DK system? What voicemail cards can be used in a DK system? Are BIOU and BDKU cards as well as DKT3000, DKT3200, or DP5000 phones backwards compatible with the system?

Thanks!