Ltr radio program

The roaming home channel is assigned when the unit registers with a site and seems to be the same for all units that register at that site. The registering channel is the frequency broadcast by neighboring sites in their "neighbor" information. LTR MultiNet systems usually have one or more "status channels" that act like a control channel in a Motorola or EDACS system, however these channels can also carry voice transmissions simultaneously.

LTR-Net networks consist of multiple sites and the network allows mobiles to roam from site to site. This configuration information enables roaming mobiles to self-configure to use the roaming site. In addition to the Home Status Channel, the site will have one or more traffic channels that transmit the normal LTR-Standard idle bursts, approximately every 10 seconds.

The LTR signalling in each of these idle bursts is identical to what the Home Status Channel is continuously transmitting. Traffic calls are normally on the traffic channels, but can spill onto the Home Status Channel when the site is busy. If there is a conflict or if the same LCN does not exist on the roaming site, the mobile will be assigned a new temporary home LCN to use on that site.

The information in slot 2 tells the other repeaters that Repeater 2 is busy. At the same time, Repeater 2 transmits the following data message:. If this data is correct, the transmitter is enabled and the handshake is complete. Since the ID code corresponds to the programmed decode ID code; the logic unsquelches the receiver. This completes the RF path between the "A" mobile and the "B" mobiles.

All mobiles with Repeater 2 as a home repeater also decode the preceding data message, which is transmitted continuously when the repeater is busy. If a mobile "B" just now comes into service, it immediately unsquelches and receives the message.

The free repeater number appearing in a repeater to mobile data message of a busy repeater is chosen randomly as described in section 5. For this example, Repeater 3 is the free repeater. When the "A" mobile finishes the transmission, the PTT switch is released and the following data message is sent before the transmitter turns off:. The "A" mobile then resumes monitoring Repeater 2. This informs the other repeaters that it is no longer busy. Repeater 2 also transmits the following data message:.

After transmitting this message, Repeater 2 resumes transmitting the idle data message shown at the beginning of this example every 10 seconds.

Note: Since the repeater is released after each transmission, this sequence of events is repeated from the beginning when one of the """ mobiles responds to this call see section 4. Assume Control Station "M" wants to call Mobile "C" while the call described in the preceding section is in progress. Figure 8 shows the system before the control station trunks to another repeater and Figure 9 shows the system after it trunks to another repeater.

This is a five-channel system and repeaters 3 and 4 are busy with other traffic. Mobile "C" can decode ID code 91 and all mobiles have repeater 2 as their home repeater. Control Station "M" decodes this message and knows that its home repeater is busy and an available repeater is 5. After this message is transmitted, the transmitter turns off and waits for a response to begin normally a few milliseconds.

The repeater logic checks the message to make sure that the area and channel are correct as described in the preceding section and then places the following information in time slot Repeater 5 also begins transmitting the following data message continuously.

This message tells all its mobiles that it is busy and Repeater 1 is an available repeater. When Repeater 2 sees its number in time slot 5, it begins to transmit an additional data message. The two data messages it is transmitting are as follows:. The first message continuously updates Repeater 2 mobiles as to which repeater is free and if any other mobiles come on line that decode ID code , they immediately receive the message.

The second message also provides updates as to which repeater is free. If a call is attempt is then made, the transmitter does not turn on when the PTT is pressed. This busy condition is indicated to the user by a busy tone. This tone continues sounding until a repeater is available or the PTT switch is released. If the PTT switch is held down, the call proceeds when a repeater is available. This feature sounds a short tone when the repeater has been successfully accessed. Refer to section 7.

When a mobile is out of range of the repeater system, it is usually the repeater that cannot decode the data message from the mobile. When this occurs, no response is made to the mobile message, so the mobile makes repeated attempts to get a response.

After several attempts are made and no response is received, the intercept tone sounds alternating high and low tones and no more attempts are made.

The PTT switch must then be released and pressed again to make more attempts. A transceiver can be programmed with ten or more systems, depending on model. Each selectable system can be programmed with a unique set of operating parameters including LTR trunked or sometimes conventional non-trunked operation. When a selectable system is programmed for LTR operation, system parameters may include home repeater, all encode and decode ID codes, call indicator and horn alert operation.

The ID codes can be fixed, selectable and block types as follows. Any combination of codes can be programmed and all codes can be different.

Note: Selectable ID codes are available only if the transceiver has a group select switch. If the transceiver has a group select switch, each group switch position selects one of the selectable decode and encode codes. If the transceiver does not have a group select switch, only one selectable decode and encode code is programmable in each system. The encode transmit ID code determines the mobile or group of mobiles being called. Only one ID code can be transmitted.

The decode codes determine what calls can be received. Group scan programming determines if all or only the selected group ID is detected. With group scanning, all are detected; without group scanning, only the selected ID is detected see section 7.

The fixed and block decode codes are always decoded regardless of which group is selected or group scan programming as long as the system is selected or scanned. Generally, when a fixed priority ID code is detected see next section , the selectable groups are checked to see if any are programmed with the priority ID code.

If one is the same, the display changes to that group. Otherwise, the display does not change. Programming a block of codes allows a group of contiguous codes to be decoded, for example, The display does not change when a block ID code is decoded.

With standard mobile-to-mobile calls, the fixed, selectable and blocked ID decode codes have a priority order so that an incoming call with a higher priority ID code can interrupt a lower priority call in progress. One use of receive priority is to allow a dispatcher to interrupt calls in progress with an important "all call" message. If the transceiver detects a call with a higher priority ID than the one it is receiving, it immediately drops that call and switches to another repeater to receive the higher priority call.

Telephone calls are not interrupted by higher priority calls. For example, if a call is being received on selectable group 4 and a call is detected on priority ID 2, the call on group 4 is immediately dropped and the transceiver switches to the call on priority ID2. Since incoming call information is received only while monitoring the home repeater, priority calls are not detected when trunked out to some other repeater or while transmitting.

To reach trunked out mobiles in this case, the priority caller can press the PTT and then not start talking for a few seconds. This should allow trunked out mobiles to return to their home repeater and detect the call. However, this may not reach mobiles making telephone calls because with those calls, the repeater is held for the duration of the call see section 4. This block may include up to all ID codes assignable on a home repeater. When an ID code within the block is decoded or selected to be transmitted, the transceiver goes into the RIC operating mode.

The system scan feature is standard with most LTR transceivers. When scanning is enabled, all programmed systems are scanned in sequence. When a call is detected that the transceiver is programmed to receive , scanning stops and the call is received. Shortly after the call is completed, scanning resumes.

If both LTR and conventional systems are programmed, both are scanned. Some LTR transceivers have a user-programmable scan list. The user can then select which systems are to be scanned. When system scanning, the home repeater of a system is monitored for only 60 ms if no carrier is detected. If a carrier is detected, the method of monitoring varies with the model of transceiver. With some transceivers, the home repeater is monitored only as long as necessary to detect any call that it is programmed to receive.

With other transceivers, the home repeater is monitored for three data messages or approximately ms. Since some messages could then be missed if the system is very busy, these transceivers can be programmed so that the revert selected system is scanned longer.

The scan time can be increased in multiples of three data messages up to eight using the scan weighting parameter. For example, if 2 is programmed, the scan time is 2 X 3 or 6 data messages.

More information on data messages is located in section 5. In the example in that section, the maximum number of messages before repeating is six. Therefore, programming 2 in that case would ensure that no messages are missed.

If information in the data messages indicates that no mobiles are being trunked out to other repeaters, only two data messages are monitored even if additional scan time is programmed. If a system has more than one selectable group, group scanning can be programmed. Calls are then detected on all selectable groups. Within group scanning, calls are detected on only the selected group. There is no separate switch that allows the user to turn group scan on and off.

If it is programmed, it is enabled whenever the system is selected. The radio is capable of the following modes of operation: analog simplex, analog conventional repeater, trunked LTR. Its small size and light weight makes it desirable choice for many operations.

Read more…….. Rent this Radio Audio Accessories. The radio is capable of the following modes of operation: analog simplex, analog conventional repeater and analog LTR trunking. Audio Accessories. Rent this Radio. This full featured radio makes it desirable choice for many operations.

The radio boasts a full set of conventional analog features including 8 character 13 segment LCD display, 4 front panel keys, FleetSync, Bi-Pin accessory connector and many other features.

The radio boasts a full set of conventional analog features including 12 character backlit dot matrix LCD display, 4 front panel keys, 2 side keys, 1 top key, FleetSync II, optional DTMF keypad, multiple scan functions, multi-pin accessory connector and many other features. This sub compact small size radio makes it desirable choice for many operations. The radio boasts a full set of conventional analog features including 8 character 13 segment LCD display, 4 front panel keys, FleetSync, multi-pin accessory connector and many other features.

Features include 10 systems and 10 groups per system, conventional channels, 8 digit LCD backlit display, 1 programmable function key, inverting front panel, QT, DQT, TOT, busy channel lockout, ignition sense, optional 12 key DTMF microphone, optional voice inversion scrambler and more.

The radio is capable of the following modes of operation: analog simplex, analog conventional repeater, analog LTR trunking, digital simplex, digital conventional repeater and digital NEXEDGE networking.

Our digital rental fleet consists of over of these radios. This radio has a wealth of robust features. Also, look for systems that have five or more frequencies, and check the licensee information for the FCC Station Class Codes.

If it is "FB2" that usually means it is a standalone dedicated or community repeater operation, not LTR. If you use the Radio Reference Database , it usually identifies trunked systems immediately. The problem with a small system that grows is that it may only have 3 out of 10 home channels assigned to users in the beginning. Finding those are easy because they are used frequently and consistent HH appear.