CTI Products EXB-232 Asynchronous Serial System Extender - Manual (Page 8)

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1.2.2 EXB-Serial Communication Channel Interface
PORT 1 and PORT 2 are standard asynchronous serial ports with individually configurable baud
rates from 1200 to 115.200 BPS. An RS-232 communication channel can be connected to each
port. PORT 1 and PORT 2 pinouts are configured for DTE operation and allow direct
connection to an RS-232 communication channel via a standard 9 pin to 25 pin cable, provided
the RS-232 communication channel is configured for DCE operation. Data format is
Asynchronous, 8 Data Bits, No Parity Bits, 1 Stop Bit (8N1).
NOTE: When the RS-232 communication channel is transmitting data to the EXB-Serial
module, the EXB-Serial module requires that the character to character gap be less than 500
milliseconds.
COM 2
COM 1
CA-80302-100
PORT 1 PORT 1
SERIAL SERIAL
CIB
HIB
T P/S
IN
OUT
OUT
T
P/S
P/S
LOCAL PC
T1
MUX
T1
MUX
CIB
OUT
IN
CIB
OUT
IN
IN
COMPARATORS
1
2
3
EXB IN
OUT IN
OUT
T T
EXB
Figure 3 - EXB-Serial System Example
The system shown in Figure 3 uses the EXB-Serial modules to connect two MCN networks
through a high speed fractional T1 circuit. For both EXB-Serial modules, PORT 1 is configured
to match the baud rate of the T1 MUX. PORT 2 on both EXB-Serial modules is disabled.
NOTE: The EXB-Serial module is configured as a DTE device. In order to use standard RS-232
cables to connect the module with the RS-232 communication channel (in this case, the T1
MUX), the RS-232 communication channel must be configured as a DCE device.
A single EXB-Serial module can interface two RS-232 communication channels to one MCN
network by enabling both PORT 1 and PORT 2. If both PORT 1 and PORT 2 are enabled, then
any data received on one port is transmitted on the other port, as well as on the Network port.
Also, any data received on the Network port will be transmitted on both PORT 1 and PORT 2.
Figure 4 shows a system configured in this way.