I looked at the system and here is what is in the slots, going from right to left
s8 empty
s7 SLI8-u10
s6 SLI8-u10
S5 SLI8-u10
S4 ESI8-u10
S3 COI4-u10
S2 CCH(4)-U10
S1 DTI-u30
ISA empty
CPU CPUB(550)-u10-ETU
based on this I know the SLI8 is 8 port single line telephone, COI4 is 4 incoming loop start lines ESI8 means 8 digital phones, I'm a little confused on the S1 & S2 slots,
I looked in the manual section and didn't specifically see the 192 listed anywhere,