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V.24
DCE-SOPHO-SET,
SOPHO-LAM or LAM
1
2B+D,( B=64kbps, user channe)l.
2
SOPHO-LAM P375 release 3 in DTE mode (!)
3
Special cable (See appendix C)
4
Modulated carrier.
Figure 3-7 Digital Connection to an Analogue Trunk with SOPHO-LAM Convertor
(Switched Line).
The DLC/DTX in this figure is one of the following boards:
-
a DLC-I;
-
a DTX-I;
-
a DLC-U/PNT1 (release 1 or 2) combination;
-
a DLC-A(B)/PNT1 (release 1 or 2) combination;
-
a DLC-C(D)/PNT1 (release 1 or 2) combination.
In the convertor configuration the SOPHO-LAM must operate in the DTE mode. In this mode
a DCE (modem) can be connected to the V.24 port of the SOPHO-LAM. Normally the
SOPHO-LAM operates in the DCE mode. The SOPHO-LAM is set in the DTE-mode using a
special signalling group for projecting the DLC or DTX-I (see Appendix C). Note that a special
cable must be connected between the SOPHO-LAM and the modem (see appendix C).
Note that it is NOT possible to use the SOPHO-LAM convertor configuration for both
incoming and outgoing calls. The SOPHO-LAM convertor is used either for incoming calls or
for outgoing calls. So, at least two convertor pools should be created, one for incoming and
one for outgoing calls.
The reason for this is that Hayes modems send strings to the SOPHO-LAM. In some situations
this can give problems. For example, during an incoming call the modem sends the string
`RING' to the SOPHO-LAM. The SOPHO-LAM does not understand this `command'. The
SOPHO-LAM echoes the string back to the modem, and the modem also does not understand
the command `RING'. Therefore for incoming calls the convertor modem should NOT send
38
1
IMP
64 kbps
2B+D
DLC/
DCE
DTX
1
SN
IMP
64 kbps DLC/
2B+D
DTX
IMP
64 kbps
ALC
IMP
64 kbps
CV
ATU
2
3
V..24
SOPHO-
LAM
MODEM
4
4
Analogue
Trunk
line
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