Datum Systems PSM-500, Инструкция по установке и эксплуатации

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PSM-500/500L/500LT SCPC Satellite Modem Installation
PSM-500/500L/500LT - Rev. 0.91 Page 2-7
Table 2–1 Data Interface
Connector J3 Pin Assignment by Signal
Modem
Pin #
RS–449 Signal Name V.35, V.36 Signal
Name
RS-232 Signal Name
*(5)
Eia-530 Signal Name Direction
28 Demod Fault Alarm
*(2) Demod Fault Alarm
*(2) Demod Fault Alarm
*(2) Demod Fault Alarm
*(2) OC TTL
output
32 Aux RS-232 Receive
*(1) Aux RS-232 Receive
*(1) Aux RS-232 Receive
*(1) Aux RS-232 Receive
*(1) Input
34 Aux RS-232 Transmit
*(1) Aux RS-232 Transmit
*(1) Aux RS-232 Transmit
*(1) Aux RS-232 Transmit
*(1) Output
37 Send Common GND
Notes on Data Interface Connections:
1. If Automatic Uplink Power Control is provided by an external multiplexer the control
channel may use the Aux RS-232 signal lines. These lines are however dedicated when
the 1:1 redundancy mode is enabled for inter-modem communications.
2. The modulator and demodulator fault alarms are Open Collector TTL outputs used to
interface to redundancy control equipment.
3. The External Data/FIFO clock pins are an input to the modem. An input at the receive
data rate can be used to clock data out of the demodulator FIFO buffer. An input at the
transmit data rate can be used to provide a transmit send timing clock which the modem
will phase locked to (if within acceptable range). The send timing signal is still an output
from the modem, but in this case will be at the input signal rate. Both functions can be
used simultaneously if the transmit and receive data rates are the same.
4. The Shield is normally connected to the cables shield at one end of the cable only.
Connecting at the DCE end only prevents ground loop currents being carried on the
shield.
5. The synchronous RS-232 connection is limited to 128 kbps.
2.3.1.1 Connecting the Data Interface to Other Equipment
The PSM-500 physical connector is that of an RS-449 interface. The electrical interface however
can be changed under front panel or remote program control to include the types of interfaces
shown above. Connecting the Data Interface to other types of equipment involves building cables
between the PSM-500 and that other equipment’s physical interface. Refer to Appendix C,
“Cabling Specifications” for more information on building and connecting these cables.
2.3.2 Remote Control Connection
The modem has a command interface serial control port which can be configured for either of two
electrical interface modes of operation. Both are located on the rear panel 9-pin female “D” sub
connector J6. Connection to either the RS–232 or RS–485 is selected by connecting to the
proper set of pins as shown in table 2-4, and setting the remote mode as applicable via the front
panel control. If the user desires a 2 wire RS-485 bus then the transmit and receive 485 lines
should be externally connected together (1 to 8 and 6 to 9).
The USB type B connection is also available for use as a remote control connection, although its
primary purpose is loading new firmware. Computers that do not have an available RS-232 port
could use of this port for control, but it requires that a special USB device driver be loaded into
the computer to access the modem via this port. This driver makes the control port appear similar
to a serial port. The latest driver is available on our web site.