Advertisement
Note that CT105 can only be used as call request provided CT108 and CT107 of the
SOPHO-LAM are ON.
It is useful to use CT105 as call request when the connection can not be cleared via CT107
of MODEM-A. In this case you can clear the connection via CT109 of MODEM-A.
When CT103 is used as call request, DTE-B can initiate a call request by typing some
characters. Note that CT103 can only be used as call request provided CT108, CT107,
CT105 and CT106 of the SOPHO-LAM are ON.
When CT108 is used as call request, the request is initiated by CT107 of MODEM-A. After
answering the call, MODEM-A activates CT107.
After the call request, DTE-B can dial the DNR of DTE-A using one of the dialling option
of the SOPHO-LAM.
• Call set-up to DTE-A
After the connection between the modems is established, DTE-B has a transparent
connection with the SOPHO-LAM convertor. Now DTE-B can dial the DNR of DTE-A
using one of the dialling protocols offered by the SOPHO-LAM (keyboard dialling, Hayes
commands or V.25bis).
TA-A activates CT125 after receiving an incoming call. TA-A answeres the call either after
receiving an active CT108 or directly when CT108 is already present.
After synchronisation and after DTE-A has activated CT105, MODEM-A receives an
active CT105. The reason for this is that the condition of CT105 of DTE-A is passed
through to MODEM-A via a frame bit (Proprietary protocol, V.110 or X.30). In fact,the
condition of CT105 of DTE-A is transferred to CT109 of the SOPHO-LAM, and CT109
of the SOPHO-LAM is connected to CT105 of MODEM-A.
Meanwhile, CT109 of MODEM-A is active, so the SOPHO-LAM is still receiving an active
signal at CT105. After synchronisation the active condition of CT105 is signalled to CT109
of TA-A via a frame bit.
After these interactions there is a transparent connection between DTE-A and DTE-B.
C.4.2. Outgoing Call
Figure
Figure C-5 Call Phase Diagram for an Outgoing Call.
an outgoing call.
shows the call phase diagram for
105
Advertisement
