help gr300 rptr to ces4700vp interconnect

[kevinvalentino]

i have been an installer and bench tech for many years on knwd equip. nothing fancy, mostly low band w/remote control stations.
i recently purchased on ebay a mot gr300 series uhf repeater, it uses 2 m120 radios and a repeater interface controller as you all probbaly know already.
my problem is i have a ces 4700vp telephone interconnect i would like to interface to the gr300. i contacted ces but got no response. it seems to me there should be a cable for direct connection but im not really educated in the wackiness of motorola.
is there such a beast available or can someone put me in the right direction with an interface schematic so i can build my own ?
any help would be greatly appreciated,
thanx,
kevin