Titan Electronics Inc NETCOM423 Manuel D’Utilisation

823RM WLAN, 1623RM WLAN  

Page 

88 

 

4.  A computer without Network access shall have at least limited 

control on the connections established by a NetCom. 

5.  Old fashioned BBS installations become accessible via Internet. 

The typical multi-modem box is replaced by a NetCom Server 
with multiple ports configured for IP Modem operation. 

A real modem provides the same signals as the serial port of a PC. 
However, where a signal is an output on the PC, it is an input to the 
modem, and vice versa. So in the NetCom the emulation of a modem 
must be incomplete. By exchanging RxD and TxD the data connection 
is fine, the same for handshaking RTS and CTS. The DTR of the PC is 
connected to DSR of NetCom, this is simple. The RI may be ignored, 
some connectors for serial ports also do that. 
However a real modem provides DSR and DCD to the PC. There is 
only the DTR left on NetCom to serve these signals. In most 
configurations the NetCom-DTR serves as the DCD to the computer. 
The cable must provide a DSR to the PC then, e.g. by shortcut to the 
PC-DTR. In some configurations the NetCom-DTR must serve as the 
DSR. This is configurable by a command. 
The recommended cable connects as shown in this table. Please note, 
this installation does not use the simply crossed signals. Especially the 
DSR of the PC is internally connected to the DTR of the PC. 

3 TxD 

----- RxD  2 3 

2 RxD 

----- TxD  3 2 

7 RTS 

----- CTS  8 7 

8 CTS 

----- RTS  7 8 

6 DSR PC-DTR

 (internal loop-back)

 

4 DTR ----- DSR  6 4 
1 DCD ----- DTR  4 6 
5 GND ----- GND  5 5 

The limitation of signals is a restriction in function, compared to real 
world serial modems.