To establish the connection, the CC searches for free internal time-slots. Let us assume that the first available time-slots are TS10 and TS11, as before. To reduce the complexity of control, the first time stage is designed as an output-controlled switch, whereas the second time stage is input-controlled.
For transfer of speech samples from the calling party to the called party of the previous example, CC orders writing of various addresses in location 10 of control memories of IT-10, OT-3 and column 3 of CM-S of corresponding to O/G highway, HWY3. Thus, 4 correspondings to I/C TS4 is written in CM-IT-0, 6 correspondings to O/G TS6 is written in CM-OT-3 and 0 correspondings to I/C HWY 0 is written in column 3 of CM-S, as shown in fig. 7.
As the first time switch is output-controlled, the writing is done sequentially. Hence, a sample, arriving in TS4 of I/C HWY 0, is stored in location 4 of SM-IT-0. It is a readout on internal HWY 0 during TS10 as per the control address sent by CM-IT-0. In the space switch, during this internal TS10, the cross point 0 in column 3 is enabled, as per the control address sent by column 3 of CM-S, thus, transferring the sample to HWY3. The second time stage is input controlled and hence, the sample, arriving in TS10, is stored in location 6 of SM-OT-3, as per the address sent by the CM-OT-3. This sample is finally, readout during TS6 of the next frame, thus, achieving the connection objective.
Similarly, the speech samples in the other direction, i.e., from the called party to the calling party, are transferred using internal TS11. As soon as the call is over, the CC erases the contents in memory locations 10 and 11 of all the concerned switches, to stop the further transfer of the message. These locations and time-slots are, then, avialable to handle the next call.
4.8 Switching Network Configuration of some Modern Switches
- E10B – T-S-T
- EWSD – T-S-S-S-T
- AXE10 – T-S-T
- CDOT(MBM) – T-S-T
- 5ESS – T-S-T
- OCB 283 – T