Adtran TRC4305 Manual Do Utilizador
Section 3, Engineering Guidelines
TRACER 4305 System Manual
30
© 2002 ADTRAN, Inc.
612804305L1A-1A
RS-232 Connection (Modem Use)
Modem controls, discussed in Section 5, User Interface Guide, of this manual, will enable or disable
modem control through the RS-232 interface. When this option is enabled from a standard terminal
connection, all RS-232 communications will cease until a modem is attached with a null modem adapter
between the TRACER 4305 and the data modem. The data modem should be configured for AUTO
ANSWER and 9600 bps. When the user connects via modem to the TRACER 4305 unit, communications
via the RS-232 port will resume. If a user accidentally enables modem control from a terminal and disrupts
the RS-232 communication, pressing <Ctrl + Z> three times will temporarily disable the modem control
option (until the system is reset) and access the system configuration to disable modem control.
modem control through the RS-232 interface. When this option is enabled from a standard terminal
connection, all RS-232 communications will cease until a modem is attached with a null modem adapter
between the TRACER 4305 and the data modem. The data modem should be configured for AUTO
ANSWER and 9600 bps. When the user connects via modem to the TRACER 4305 unit, communications
via the RS-232 port will resume. If a user accidentally enables modem control from a terminal and disrupts
the RS-232 communication, pressing <Ctrl + Z> three times will temporarily disable the modem control
option (until the system is reset) and access the system configuration to disable modem control.
The TRACER 4305 must be interfaced to a modem via an RS-232 null modem adapter or cable. The null
modem will convert Clear To Send (CTS) and Data Set Ready (DSR) into Ready To Send (RTS) and Data
Terminal Ready (DTR), respectively. These signals will indicate (to most modems) that a valid DTE
terminal device is present. The null modem interface must route Carrier Detect (CD) on pin 8 directly from
the modem, and the modem must source CD only when actually connected to a carrier when using the
RS-232 interface for modem control.
modem will convert Clear To Send (CTS) and Data Set Ready (DSR) into Ready To Send (RTS) and Data
Terminal Ready (DTR), respectively. These signals will indicate (to most modems) that a valid DTE
terminal device is present. The null modem interface must route Carrier Detect (CD) on pin 8 directly from
the modem, and the modem must source CD only when actually connected to a carrier when using the
RS-232 interface for modem control.
When
M
ODEM
C
ONNECTION
is selected in the menu system, the TRACER 4305 will de-assert DTR and
DSR for a time greater than 20 ms. The null modem will consequently drop DTR and RTS at the modem
interface, signaling the modem to hang up the line. If password functionality is enabled in the TRACER
4305, selecting
interface, signaling the modem to hang up the line. If password functionality is enabled in the TRACER
4305, selecting
M
ODEM
C
ONNECTION
will rest the TRACER 4305 to the password entry screen.
Table 8 contains the wiring diagram needed for connecting the TRACER 4305 RS-232 interface to a
modem using the null modem adapter.
modem using the null modem adapter.
Hangup-on-DTR-drop may need to be explicitly enabled on some modems.
Table 8. TRACER 4305 (DCE) to Modem (DCE)
PIN
NAME
PIN
NAME
2
TX
3
RX
3
RX
2
TX
4
RTS
5
CTS
5
CTS
4
RTS
6
DSR
20
DTR
7
GND
7
GND
8
CD
8
CD