Concentrated energy from a directional antenna may pose a health hazard to
humans. Do not allow people to come closer to the antenna than the distances
listed in the table below when the transmitter is operating. More information on
RF exposure can be found online at the following website:
www.fcc.gov/oet/info/documents/bulletins.
Antenna Gain vs. Recommended Safety Distance
Device complies with Power Density requirements at 20 cm
No
separation:
Required separation distance for 9 dBi antenna (in m):2.53
Above data based on a 30-watt output level with a 100% duty cycle.
FCC Part 15 Notice
The transceiver is approved under Part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) this device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation. Any unauthorized modification
or changes to this device without the express approval of Microwave Data Systems may void the user’s
authority to operate this device. Furthermore, this device is intended to be used only when installed in
accordance with the instructions outlined in this manual. Failure to comply with these instructions may
void the user’s authority to operate this device.
INTRODUCTION
This guide presents basic installation and operating instructions for the
GE MDS TD 220 Series wireless transceiver.
The TD 220 operates in two bands and power levels:
• 25-Watts in the 220-222 MHz range
• 2-Watts in the 217-220 MHz range
The radio is a GMSK unit intended for bridging ITCS messages over
the air between locomotives and wayside devices. The data interface
is Ethernet, with UDP-encapsulated ITCS message payload.
Figure 1. TD 220 Data Transceiver
NOTE:
Each second is divided into 8 133-byte time slots. The first of the 8
timeslots each second is always reserved for bases to transmit beacon
information to the mobiles in the area. Following the beacon are 4 (or
5) time slots that are always reserved for mobiles to transmit. At the
end of each second, are 3 (or 2) time slots that can be used by bases or
mobiles. These slots are used with the following priority: the previous
base, the current base, and then mobiles. In other words, during second
1 in the table below, base A actually has priority over the last three
slots. If A does not use them, B can use them. If B does not use them,
mobiles can. Bases reserve these time slots with flags in the beacon.
This scheme maximizes the potential for utilizing all slots.
Some features may not be available on all units, based on the
options purchased and the applicable regulatory constraints
for the region in which the radio will operate.
1
1
DATA INTERFACES
DB-25
Figure 10 shows the pin arrangement for the DB-25
connector. Table 1 lists the pin functions and shows
The radio provides a USB Port conforming to version 1.1 of the USB
standard. This port is provided for future features such as ITCS logging to text files on a memory stick. Consult GE MDS for information
on this feature. The pinout for this connector is given in the table
below.
Table 4. Current/Voltage Requirements vs. RF Output
Voltage (Vdc)RF Output (W)Current Required (A)
13.80 (RX)TBSL
13.82TBSL
13.810TBSL
13.825TBSL
Antenna Connector
The Antenna Connector is a Type-N female connector with 50-Ohm
characteristic impedance.
Common Setup Tasks
Key the Transmitter for Test Purposes
1. Log in to the radio on its COM1 console using a serial terminal
emulator program.
2. Go to the Radio Configuration menu.
3. Select the frequency for the test transmission.
4. Select the RF Output Power to use. Note that power levels greater
than 2 Watts will timeout after a 5-second period by default.
Ensure ventilation with supplemental forced airflow if longer
durations are desired.
5. Select the Force TX Key menu option.
6. When finished, deselect the Force TX Key menu option.
Prepare the Network Interface for a Radio
Each radio is assigned an IP Address, a Netmask, and a Gateway IP
Address. The IP Address and Netmask should be chosen carefully.
The radio will network directly with other equipment with IP
Addresses that are on a common Subnet. IP Addresses that begin with
the same numerical IP address bits where the Netmask is one will be
on the same Subnet. For example, if the IP Address is 10.4.100.1 and
the Netmask is 255.255.0.0, the radio will attempt direct Ethernet
communication with any node whose IP Address begins with 10.4. If
a message is bound for a node outside of the 10.4 network, it will be
sent to the Gateway IP address instead so that it can be placed from the
radio's subnet onto another subnet.
1. Log in to the radio on its COM1 console using a serial terminal
emulator program.
2. Go to the IP Configuration menu.
3. Set the IP address of the radio, plus the Netmask and Gateway.
4. Go to the Maintenance/Tools Menu and select the Ping Utility.
5. Enter the IP address of a known node on the network.
6. Execute the Ping and observe the results. If the network interface
is working properly, Ping responses should be received.
Set Up a Base Unit
1. If not already done, complete steps from 3.2 above.
2. Log in to the radio.
3. Go to the System Configuration menu.
4. Set the unit to Base mode and reboot if necessary.
5. Set the base type (A, B, or C).
6. Set the window size. Mobiles will transmit in a randomly selected
available slot among 2^(Window Size) slots. For small networks,
this can be 1. For larger networks, use a Window Size that provides double or quadruple the number of mobiles expected under
one base at a time.
7. Set the IP Port on which the base will receive UDP messages from
wayside devices.
8. Set up an ITCS Translation Table. For test purposes, this may be
as simple as setting up one known address with a mask of all
“If’s”.
9. Verify Ethernet Link using the Ping utility in the Maintenance/Tools Menu.
10. Begin sending UDP data.
11. Verify the TX LED illuminates and the radio begins transmitting
over the air.
1. If not already done, complete steps from 3.2 above.
2. Log in to the radio.
3. Go to the System Configuration menu.
4. Set the unit to Mobile mode and reboot if necessary.
5. Set the IP Port to which the mobile will send messages received
over the air.
6. Set the IP Port on which the mobile will accept incoming messages for transmission over the air.
7. Verify Ethernet Link using the Ping utility in the Maintenance/Tools Menu.
8. Ensure at least one base is present in the neighborhood of this
radio so that it can detect beacons and synchronize timing.
9. Begin sending UDP data from a polling program.
10. Verify the TX LED illuminates and the radio begins transmitting
over the air.
3.5 Perform Test Polling
1. Set up the Base and Mobile as above.
2. Connect as shown in the following diagram. Note: this is for
bench testing only, i.e. not for sensitivity testing. Sensitivity testing requires complete RF isolation or mixed operation to prevent
the leakage path from being the dominant RF path between units.
For bench testing, use attenuation so that the signal level at every
unit that is participating is around -70 to -50 dBm.
12. Click Start Polling on both units and observe the message counts
and sequence number increment.
13. If additional visibility is desired, obtain
itcslog.exe
from GE MDS.
This utility captures messages from the logging output of the
TD220 radios and displays statistics about them. The IP Port
Number is the port number configured on the radio for ITCS logging.
will pass traffic from the radio's
subnet to nodes on other networks.
Table 9. System Configuration Menu Items
ParameterR/WDescription
A) Unit TypeR/WBases send beacons out once per
epoch and coordinate downstream
messages. Mobiles listen to bases
to identify free slots, and then select
random slots in which to place their
upstream messages.
B) Base Unit ZoneR/WBases are one of three types, A, B,
and C. Each base coordinates slots
in the epoch assigned to that base
and transmits downstream. Base
types repeat along lines of track (A,
B, C, A, B, …)
32-bit Destination ITCS Address, a
32-bit ITCS Address Mask, an IP
Address and port, and the RSSI
Option. Any incoming ITCS
message is bitwise anded with the
mask. If the result matches the
Destination ITCS Address, the
message is sent to the IP Address
and Port given. If the RSSI Option is
“yes”, the over the air Received
Signal Strength Indication is
prepended to the data message in
the UDP transmission.
The following chart shows how RSSI Data (shaded portion) is
prepended to standard ITCS Data within the UDP packet.
Configuration scripts are used to store and duplicate radio settings. To
use this facility, send the configuration file from a radio to the TFTP
server. It can then be archived or edited and retrieved from the same
or different radios. For more information, contact GE MDS.
Table 24. xxxxx
ParameterR/WDescription
A) Address to PingR/WThe IP address of the network host
Below are the basic steps for installing the transceiver. Refer to
Figure 6 as necessary to make the cable connections.
1. Mount the transceiver to a stable surface using the brackets
supplied with the radio. Begin by attaching the radio’s mounting
brackets to the bottom of the transceiver case (if not already
attached) using the four 6-32 x 1/4 inch (6 mm) screws supplied.
Figure 7 shows the mounting bracket dimensions.
NOTE: To prevent moisture from entering the radio, do not mount the
case with the cable connectors pointing up. Also, dress all
cables to prevent moisture from running along the cables and
into the radio.
Using screws longer than 1/4 inch (6 mm) to attach the
brackets to the radio may damage the internal PC
board. Use only the supplied screws.
2. Install the antenna and feedline for the station. The antenna
used with the transceiver must be designed to operate in the
radio’s frequency band, and be mounted in a location that provides a clear, path to the other associated station(s). Use low loss
coaxial feedline and keep the cable as short as possible.
3. Connect the data equipment to the DATA INTERFACE connec-
tor. Check SPECIFICATIONS on Page 47 for pin wiring details.
Note: The radio’s DIAGNOSTICS port is used for reprogramming
the radio’s firmware.
4. Connect primary power to the transceiver. Power applied must
be within 10.5–16 Vdc and capable of continuously providing at
least 8 Amperes. A power connector with is provided with each
unit (see Figure 6).
CAUTION
POSSIBLE
EQUIPMENT
DAMAGE
The transceiver is designed for use with negative-ground systems only. The power supply should be
equipped with overload protection (NEC Class 2 rating),
to protect against a short circuit between its output terminals and the radio’s power connector.
5. Set the radio’s configuration. The transceiver is designed for
quick installation with a minimum of software configuration
required.
a.Connect a PC to the transceiver’s
DATA INTERFACE connec-
tor as shown in Figure 8. If desired, a cable may be built using
the information shown on Page 47 of this guide.
b.Launch a terminal communications program, such as Hyper-
Terminal (included with most Windows
ENTER
key a few times (at half-second intervals) to receive
TM
systems). Press the
the ready “>” prompt on the screen.
NOTE: To prevent unintended keying of the transmitter during
Display internal spectrum analyzer, where
xxx.xx characters denote center frequency
in MHz. The command spectrum may be
entered alone to view current operating
channel.
TEMPDisplay the internal temperature of the radio
TX [xxx.xxxx]Set or display the transmit frequency.
For proper operation, all radios in the network must meet these basic
requirements:
• Adequate and stable primary power
• Secure connections (RF, data and power)
• A clear transmission path between stations
• An efficient antenna system providing adequate received signal
strength.
• Proper programming of the transceiver’s operating parameters
• The correct interface between the transceiver and the connected
data equipment (correct cable wiring, proper data format, timing, etc.)
LED Indicators
The LED status indicators (Figure 9) are an important troubleshooting
aid and should be checked whenever a problem is suspected. Table 26
describes the function of each status LED on the front panel of the
radio.
DCDWhen lit, indicates that a communication link is established
with the other station(s).
Event Codes
When an alarm condition exists, the transceiver creates a code that can
be read on a connected terminal. These codes can be helpful in
resolving many system difficulties. Refer to Table 27 (Page 45) for a
definition of the event codes.
Checking for Alarms—STAT command
To check for alarms, connect a terminal to the radio’s DIAGNOSTICS
port. See SPECIFICATIONS on Page 47 for pinout information.
STAT on the connected terminal. If no alarms exist, the message
Enter
NO ALARMS PRESENT appears on the display.
If an alarm does exist, a two-digit alarm code (00–31) is displayed and
the event is identified as a Major or Minor Alarm. A brief description
of the alarm is also given.
Major Alarms—report serious conditions that generally indicate a
hardware failure, or other abnormal condition that will prevent (or
seriously hamper) further operation of the transceiver. Major alarms
generally indicate the need for factory repair. Contact your factory
representative for assistance.
Minor Alarms—report conditions that, under most circumstances will
not prevent transceiver operation. This includes out-of-tolerance conditions, baud rate mismatches, etc. The cause of these alarms should
be investigated and corrected to prevent system failure.
Event Code Definitions
Table 27 contains a listing of event codes that may be reported by the
transceiver. The codes shown are a subset of a larger pool of codes
used for various GE MDS products. For this reason, the table does not show a sequential listing of all code numbers. Only the codes applicable to this product are shown.
Table 27. Event Codes
Event
Code
01MajorImproper software detected for this radio model.
04MajorThe RF synthesizer is reporting an out-of-lock
08MajorThe system is reporting that it has not been
12MajorReceiver time-out. No data received within the
13MinorA Transmitter timeout was detected. The radio
17MinorA data parity fault has been detected on the
18MinorA data framing error has been detected on the
calibrated. Factory calibration is required for proper
radio operation.
specified receiver time-out time.
stayed keyed longer than the duration specified by
the TOT command.
PAYLOAD port. This usually indicates a parity
setting mismatch between the radio and the
customer equipment.
PAYLOAD port. This may indicate a baud rate
mismatch between the radio and the customer
equipment.
Table 27. Event Codes (Cont’d)
Event
Code
26MinorThe DC input voltage is out-of-tolerance. If the
31MinorThe transceiver’s internal temperature is
Event
ClassDescription
voltage is too far out of tolerance, operation may fail.
approaching an out-of-tolerance condition. If the
temperature drifts outside of the recommended
operating range, system operation may fail.
Internal Spectrum Analyzer
The radio contains a built-in spectrum analyzer tool (Figure 10) that
can be displayed on a connected PC. The tool is helpful in diagnosing
interference problems on or near your channel frequency.
Access the spectrum analyzer by entering
prompt. A display appears showing detected signals on your current channel.
Optionally, you can specify a frequency at the command prompt to
view the surrounding spectrum of that frequency. To do this, enter
spectrum xxx.xx, where xxx.xx is the frequency in MHz.
As shown in Figure 10, the display creates a received signal strength
indication (RSSI) vs. frequency plot for the frequency and surrounding signals. By analyzing the display, you can determine the
presence of other signals near the transceiver’s operating frequency.
This information can be helpful in troubleshooting interference problems.