M1A1 tank coming ashore

An M1A1 tank from 2d Brigade, 3d Infantry Division, comes ashore during Exercise Native Atlas '02, a joint (JLOTS) exercise conducted by both the Army and Navy.

Ruggedized commercial-off-the-shelf voice switch supports joint exercise

by MSG Alan DeWitt

Army tactical wireline communication is based around two systems: mobile-subscriber equipment, which allows access to the Area Common-User System for battalion-size elements and higher, and the venerable TA-312 field telephone and SB-22 switchboard for internal communications at battalion and below. While these communications solutions work well in a traditional mission setting, they don�t always meet the command-and-control needs of units conducting operations and exercises in non-traditional roles.

This fact is even truer with combat-support and combat-service-support units. Case in point: the recent Joint Logistics Over The Shore exercise Native Atlas 2002 conducted by the Army and Navy at Camp Pendleton, Calif.

Native Atlas� purpose was to discharge 2d Brigade, 3d Infantry Division�s equipment from a roll-on/roll-off ship two miles off the California coast near Camp Pendleton, then move it inland to the National Training Center at Fort Irwin, Calif., so the brigade could conduct its annual rotation. This exercise was very similar to a wartime mission in which units would deploy soldiers by air to the operations area and fall in on equipment unloaded from a prepositioned RORO ship.

The 32d Transportation Group commanded all Army Forces participating in the exercise. The ARFOR consisted of both active-duty and Reserve transportation, quartermaster and military-police units.

Communications challenge

Last-minute retasking of coordinated Signal support required units participating in Native Atlas to rely on organic communication capability. However, even if an MSE-equipped Signal unit had been available to support the exercise, its capabilities wouldn�t have �translated� well to the participating units� C2 requirements. Because of the exercise�s size and scope, ARFOR units required long-haul communications to coordinate with other military units and civilian/government agencies spread throughout the United States. These external organizations didn�t have access to tactical �green phones.� For this reason, access to the Defense Switched Network and Public Switched Telephone Network was paramount to the exercise�s success, but access was extremely limited due to the base camp�s isolated location on the vast Camp Pendleton reservation. ARFOR�s total DSN allocation was only 10 lines to support 15 units at multiple locations in the base camp.

Non-traditional operations call for non-traditional solutions. In this case, the solution came in the form of a small, ruggedized commercial voice switch aptly named Warrior PBX.

Answer: Warrior PBX

Warrior PBX is a small, deployable, commercial-off-the-shelf voice switch, or private branch exchange, which supports up to 32 subscribers and 12 analog trunk terminations. (An optional upgrade allows for 48 subscribers and 16 trunks.) Subscriber equipment can be commercial wired and wireless telephones, fax machines, computer modems, Secure Telephone Unit-III / secure-terminal-equipment telephones, and even TA-312s with dual-tone multifrequency adapters. The trunk interface is a loop-start circuit allowing connection to standard analog DSN and PSTN phone lines.

Also, Warrior PBX is able to interface with MSE�s large extension node, small extension node and force-entry switch for connectivity to ACUS. Even without outside connectivity, the system can act as a full-featured, closed-voice network exponentially more powerful than the current field phone system. Subcomponents of the system include an uninterruptible power supply, extension and trunk distribution panels, a system computer and an operator�s hands-free telephone set mounted to a sliding shelf.

All components are mounted to a 19-inch aluminum rack contained inside an olive-drab-colored Hardigg transport case. The rack is isolated from the case by eight rubber mounts that absorb any shock or vibration during movement, allowing the equipment to withstand some rough handling. Weighing only 165 pounds and taking up just 27 inches by 27 inches of floor space, Warrior PBX is relatively small when compared to the tremendous capability it brings to the fight.

Native Atlas use

The 24th Transportation Battalion took Warrior PBX to Native Atlas intending to use it to support the battalion�s own C2 requirements. The 32d Transportation Group quickly decided that Warrior PBX would provide greater service supporting the entire ARFOR element. This decision not only increased access to the DSN network by more than 300 percent, but it also improved the quality and capability of internal communications among ARFOR units in the base camp.

Each of the 32 extensions was judiciously assigned to maximize impact. All 10 of the allocated DSN lines were terminated to the trunk side of the switch. Coordination was made with Camp Pendleton�s directorate of information management to place each of the 10 telephone numbers into a hunt group. By placing all DSN numbers in a hunt group, incoming calls would automatically search for the first available open line. This action allowed exercise participants to give out only one access number to outside callers.

Terminating trunks and extensions to Warrior PBX was extremely easy due to the system�s tool-less distribution panels. The screw-down binding posts don�t require any special tools to terminate wire connections and can be used with either military field wire, such as WF-16 and WD-1, or commercial-grade wire, such as two-pair Category-3 and four-pair Category-5 cable. A mix of WF-16 and Category-5 cable was used to connect trunks and extensions during Native Atlas. While most cable runs were less than one kilometer, the system will support extension and trunk connections up to five kilometers.

Testing extension lines on Warrior PBX

SPC Dennis Braun tests extension lines on the Warrior PBX during Exercise Native Atlas '02.

After Signaleers connected the trunks and extensions, it was time to program the switch. The system computer, mounted on a sliding tray inside the transport case, allows full programming of the switch, monitoring of the system�s UPS and ability to automatically log all call activity. The only programming requirement is that the installer knows the number of trunks and extensions connected to the system. With this information, the installer consults a configuration matrix to determine the name of the required configuration file. The configuration file is opened on the system computer and then uploaded into the switch via a serial-cable connection. Once loaded, the switch is fully operational. Total set-up time during Native Atlas was two hours, with most of that time consumed laying cable and connecting end-user equipment.

Programming Warrior PBX

PFC Sharonda Freeman programs Warrior PBX.

ARFOR units began using Warrior PBX minutes after installation was complete. Call volume during the exercise�s peak was extremely heavy but very rarely saturated the trunk lines. The loop-to-trunk ratio was 3.2-to-1, which provided a high probability of trunk seizure equating to a high quality of service. As a good rule of thumb, the manufacturer recommends a ratio of no higher than 4-to-1 to ensure an acceptable QoS. Depending on your subscribers� calling characteristics, you may increase this ratio with minimal impact on QoS. In situations where subscribers far outnumber trunks, it�s possible to limit trunk access to only select subscribers � other subscribers will still be able to take advantage of the internal network but can�t place external network calls.

Operating procedures for the subscriber were simple and easily comprehensible. If an ARFOR subscriber wanted to call another ARFOR subscriber, he would simply dial a three-digit extension. For access to DSN, the subscriber would dial �9� to seize the first available trunk. When he heard the second dialtone, he could then dial the DSN or commercial number he wanted to call.

Subscribers also had access to features normally only found on their garrison telephone network like six-party conference call, call waiting, call forwarding, transfer, hold, hunt groups and pick-up groups. (Warrior PBX supports more than 100 features.) Units requiring secure communications connected STU and STE phones to Warrior PBX to conduct secure calls.

Voice quality on Warrior PBX is extremely clear due to the 64-kilobits-per-second sampling. This is the same channel size used on the commercial telephone network. The difference in voice quality is quite remarkable when compared with MSE�s 16-kbps voice channel.

For incoming calls, Warrior PBX automatically greets callers with a prerecorded message asking the caller to enter the extension of the unit he or she wishes to reach. A unit can customize this 20-second message. Incoming fax calls are automatically detected by the switch and routed to a predetermined extension.

Warrior PBX performed flawlessly, providing uninterrupted service during the 30-day exercise. The hot, dusty, harsh environment of Camp Pendleton didn�t faze the internal system components. Thanks to the internal UPS, the system remained operational even when base-camp power-distribution problems led to blackouts lasting more than an hour. The UPS battery is so powerful that the system can remain operational for up to three hours without external power.

Warrior PBX�s strengths

Warrior PBX�s many capabilities saved ARFOR both time and resources. One such savings was the reduction in the number of cable runs. With Warrior PBX, a subscriber�s single telephone connection had access to both the internal and external network. Without this support, subscribers would have required both a DSN and TA-312 connection. In addition, a soldier was freed up from operating the field phones� manual SB-22 switchboard.

Another timesavings was gained by streamlining procedures for changing a telephone line�s class of service. Normally any changes to a line�s CoS would require exercise personnel to submit a local-service request to the DOIM. Depending on DOIM�s workload, the request could take anywhere from a few hours to a few days to process. For a short exercise, this wait could be painful. During Native Atlas, all trunk lines were marked Class A, the highest possible CoS. Using Warrior PBX�s system computer, subscribers� extension lines were given a CoS appropriate to their mission. When a change to a subscriber�s COS was required, it was done in minutes with only a few mouse-clicks on the system computer.

Another capability that potentially saved ARFOR hundreds of dollars was the call-detail reporting feature. This feature is especially useful because it automatically documents all incoming and outgoing trunk calls in real time. The report displays the time of the call, the call�s duration, which extension made the call, the number called and the trunk used. The report can be saved electronically as a text file or printed out, meeting Army Regulation 25-1�s requirement that all toll calls be recorded on a log. Call-detail reporting is especially useful in identifying and eliminating toll-call abuse before it becomes a major expense. In the past, units wouldn�t have realized abuse had occurred until after the damage had been done when they received the post-exercise phone bills. With real-time call-detail reporting, toll-call abuse can be quickly pinpointed and action taken. Warrior PBX allows you to block calls to area codes and specific phone numbers for each or all extensions.

Post-exercise maintenance of the system was straightforward, simple and quick. After we returned to home station, we wiped down the system case and components, and used compressed air to clean dust from circuit cards and fan intakes. Lastly, we visually inspected the extension and trunk distribution panels and wiring connections for any damage. Once cleaned and inspected, the system was secured in a storage facility to await its next mission.

As the pace of technological innovation quickens, COTS equipment will continue to play a larger role in our tactical and strategic communications infrastructure. Warrior PBX, a perfect example of blending COTS technology with military ruggedization, was the right solution for ARFOR�s C2 needs during Native Atlas �02.

The application potential for Warrior PBX is enormous. Its ability to interface with a wide array of equipment and networks, both military and civilian, and its ability to use secure communications make it an asset for not only continental-U.S.-based exercises but also real-world operations. It can provide C2 support to command posts, field hospitals, logistic/support bases and other organizations connected by tactical and commercial networks, or even through point-to-point tactical-satellite connections at isolated locations. It�s affordable and extremely easy to operate, allowing even non-Signal units at battalion level to install, operate and maintain it. The fact that it was installed, operated and maintained by a small communications section of industrious 31U soldiers in a transportation battalion speaks volumes about just how easy this powerful system is to use.

Tactical Telecom LLC manufactures Warrior PBX. You can find more information on the company�s ruggedized COTS products by visiting its website at www.tacticaltelecom.com.

MSG DeWitt is 24th Transportation Battalion�s communications chief at Fort Eustis, Va. He has more than 16 years of tactical Signal experience and has spent the last two years expanding his battalion�s C2 capabilities by exploiting COTS equipment.

Acronym QuickScan
ACUS � Area Common-User System
ARFOR � Army forces
C2 � command and control
CoS � class of service
COTS � commercial-off-the-shelf
DOIM � directorate of information management
DSN � Defense Switched Network
JLOTS � Joint Logistics Over the Shore
Kbps � kilobits per second
MSE � mobile-subscriber equipment
PBX � private branch exchange
PSTN � Public Switched Telephone Network
QoS � quality of service
RORO � roll-on/roll-off
STE � secure terminal equipment
STU � secure telephone unit
UPS � uninterruptible power supply

dividing rule

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