Using old wiring - general cable c cmx 3 pair

I’ve been installing asterisk for a company that is moving to an old warehouse/production facility. The building has been added on to several times, and there is a variety of wiring installed throughout.

There are any number of phone jacks that were installed using Cat3 cable, and I have successfully wired them up to rj45 ends/keystone jacks for use with Asterisk.

There is a nasty old phone patch panel in the back of the place that i was hoping to avoid, but it turns out that many of the phone jacks do terminate back there.

All the phone cabling back there uses cable that has the notation “General Cable C CMX Outdoor - MP/CM 3PR 22 (UL) SW 1991.” The cable has what looks like 3 non-twisted pairs of conductors that are colored black, white, yellow, blue, green and red. Is there any way I can use this with asterisk? Specifically, can I get this to work with Cat5 keystone jacks and ends?

Thanks much for any assistance.