Advertisement
-
support of almost all modems (including Hayes modems);
-
support of all current asynchronous speeds up to 19200 bits/sec;
-
support of V.110, X.30 and Proprietary Data Rate Adaption.
Disadvantages:
-
full support of only three synchronous speeds (4800, 9600 and 19200 bits/s);
-
automatic convertor interconnection is not possible (convertor DNR and destination
DNR have to be dialled).
Leased Line Configuration with MLU
For trunk or tie-lines which are restricted for data use only, the line is connected directly to
the modem. Voice calls are not possible over such lines. For this type of connection set-up the
same requirements of number analysis, traffic classes and compatibility values must be fulfilled
as for the DTE connected via a modem to the ALC.
In this case no ATU is needed and also no path from the MLU to the ATU through the
switching network has to be set-up. The configuration of such a leased line connection is
shown in figure
Figure 3-3 Digital Connection to an Analogue Trunk with MLU Convertor
(Leased Line).
V.24
DCE
DCE-SOPHO-SET,
SOPHO-LAM or LAM
1
2B+D, B=64kbps, user channel.
2
Modulated carrier.
Figure 3-3 Digital Connection to an Analogue Trunk with MLU Convertor (Leased Line).
Call progress is as follows:
-
For an outgoing data call. When a DTE dials the trunk access code to the destination a free
line (modem) is selected in the route to that destination and a direct data connection is
established (a modem-modem connection). It is not possible to send additional dial
information to the external network using the MLU and modem.
-
For an incoming data call. When the modem is idle and detects a carrier on the line, an
incoming seizure is initiated. It is not possible to receive additional dial information. The
1
IMP
2B+D
64 kbps
DLC/
DTX
SN
IMP
64 kbps
MLU
MODEM
V.24
2
Trunk
line
29
Advertisement
