To the venue owner – an ERRCS system is an expense with no ROI.

To the Emergency Responder – an ERRCS system is a MUST – with life safety for
responders, AND the public, depending on it.

Comba Telecom is committed to providing highly affordable,
state of the art solutions so venue owners can ensure
that First Responders get the coverage they need and deserve,
while making the cost to the venue owner as low as possible.


Comba's CriticalPoint Class A 700MHz/800MHz single or dual band channelized Fiber DAS was designed with public safety first responders in mind. Fully compliant with the IFC and NFPA (National Fire Protection Association), CriticalPoint's Fiber DAS supports up to 32 channels (700MHz and 800MHz) along with 2W (Remote Unit) of downlink power per band. The channelized uplink squelch and channelized uplink AGC functions ensure minimum interference to base stations and optimizes communications quality.

It includes comprehensive alarming capabilities, which supports all NFPA and IFC required monitoring and alarming, and also provides local and SNMP based remote monitoring. The built-in signal generator and isolation testing function provide great convenience to system integrators during deployments. Finally, the unit can be ordered either AC or 48V DC powered, allowing for flexibility depending on the design of the system.

In addition, by utilizing Comba's well-known high efficiency amplifier design, the Fiber DAS provides a very small footprint, light weight design, low electrical operating costs, and low UPS backup costs. Comba's total vertical in house design and manufacturing capabilities, and supply chain management resources, ensures that the CriticalPoint Fiber DAS is a very affordable, reliable and state of the art.

*Public Safety Fiber DAS MU FOU Expansion Unit, 4 port/8 port now available.

Null Single or dual band
Null Supports
up to 32
channels per
Null 2W output
power for each
band. ½W version
Null Channelized
uplink (AGC)
Null Channelized uplink
squelch supported
Null Web based
GUI for
fast and easy
Null Built-in
isolation test to
prevent BDA
Null NFPA compliant dry
contact alarms,
NEMA 4 enclosure


Product Type
Part Number (AC Ver)
Part Number (DC Ver)
Class A
MU Dual Band 700/800MHz, 1 to 4 x RUs, DC-48V


MU Dual Band 700/800MHz, 1 to 8 x RUs, DC-48V


RU Single Band 700MHz, DC-48V
RU Single Band 800MHz, DC-48V
RU Dual Band 700/800MHz, DC-48V
Expansion Unit - 4 Port
Fiber DAS MU FOU Expansion 4 port
Expansion Unit - 8 Port
Fiber DAS MU FOU Expansion 8 port

How can Comba offer so much for such a low price?
Comba is a prime manufacturer – we internally design and manufacture many sub components and sub assemblies that other OEMs outsource (PCBs, PCB insertion and wave soldering, metal chassis components, key passive components, power amplifiers, etc.).

This provides Comba with much lower cost – and in addition, internal manufacturing also allows us to maintain a higher level of quality control and better control over lead times.

How does Comba CriticalPoint have such low AC power consumption?
Comba utilizes High Efficiency Linear amplifier design – linear amplifiers draw significantly less operating current than conventional amplifier designs.

How does Comba CriticalPoint have such low weight?
This is another advantage of High Efficiency Linear amplifier design – extremely low weight. It is also important to note that since the Linear amplifiers generate less heat, there is no need for cooling fans – this also contributes to lower weight.

In addition, Comba's design team puts forth great efforts to ensure that there is no "over design" of any part of the CriticalPoint products, that could result in unnecessary extra weight or cost.

If I ordered a single band version and discover that I need the other single band instead, do I need to return the original unit and re-order the correct band version?
No – the CriticalPoint single band Fiber DAS include a license to switch from one single band to the alternate single band. No additional purchases are required.

Does upgrading to add the second band require an onsite visit?
Not necessarily – if there is network access via modem or Ethernet available, the CriticalPoint BDA upgrade license can be installed remotely.

Does making adjustments to the CriticalPoint product require an onsite visit?
Not necessarily – if there is network access via modem or Ethernet available, the CriticalPoint BDA can be commissioned, adjusted, and monitored remotely. Modem/Ethernet access and SNMP v2/v3 are fully supported.

Is special battery back up equipment required for compliance with AHJ requirements?
No – CriticalPoint will work with any standard commercially available UPS or battery backup system.

I see that the CriticalPoint Fiber DAS provides up to 32 channels for each band – can channels from one band be allocated for more than 32 channels in another band?
No – there is a maximum of 32 channels for each band deployed.

I see that the CriticalPoint Fiber DAS claims 2W of power per band? Is this true, or is the 2W shared across both bands?
The CriticalPoint Fiber DAS provides 2W of downlink power for EACH BAND independently.

Does CriticalPoint provide any built in oscillation protection?
Yes – CriticalPoint protects against oscillation in 2 ways:

First, there is a mandatory isolation test that must produce satisfactory results prior to being able to commission the Fiber DAS.

Secondly – in the event that something changes the isolation (and causes oscillation) while the Fiber DAS is in use, the CriticalPoint BDA will shut down and issue an alarm.

What is the warranty for the CriticalPoint Fiber DAS?
All Comba products have a 3 year product warranty with advanced exchange service.

What approvals or compliance ratings does the CriticalPoint product carry?
The CriticalPoint BDA is FCC, UL and IC approved – and it is fully NFPA and IFC compliant. In addition, the unit is housed in a NEMA 4X rated chassis.

Comba tests and certifies it's products through a Nationally Recognized Test Lab (NRTL) to meet the strict UL requirement standards. Click to view Comba's UL Standards Testing and Product Certification process pdf.

Does this Fiber DAS carry both analog and digital communications – and can it do so simultaneously?
As our specification sheet states – our Fiber DAS is compatible with and capable of passing analog and digital communications, and simultaneously.

How does this work: our Fiber DAS amplifies and passes RF (radio frequency) – RF can carry analog traffic, or it can carry digital packetized traffic. As stated, our Fiber DAS is simply amplifying and passing the RF - we do not read, manipulate, or modify, nor really even "see" or know, what the traffic content is.

A way to look at this: consider the Fiber DAS and the antenna infrastructure as plumbing in a home or building – all the plumbing does is carry water. The water can be hot water or cold water - or could be potable or non-potable water – the plumbing doesn't care. And in a similar fashion, our Fiber DAS does not care what the traffic content over the RF is comprised of.

So how can analog and digital, which are different, be carried simultaneously? The end devices (base station and mobile devices) operate on either analog or digital – meaning that an analog device won't even see the digital traffic, and the digital devices won't even see the analog traffic. So – both types can be mixed over the same RF path with no chance of one interfering with the other.

I am getting call quality issues with my group delay settings at 12.5KHz and 25KHz. What can be done to fix this?
In certain cases when deploying a Class A BDA in a P25 Phase I/II network environment, the typical 12.5KHz or 25KHz channel bandwidths with their higher level of group delay may cause some issues with call quality and clarity. A channel bandwidth of 12.5KHz may result in group delay figures of up to 35usec; 25KHz channel bandwidths may result in group delay figures of up to 27usec – either of which can cause call quality issues as mentioned above.

To minimize or eliminate any call quality issues resulting from using these very narrow channel bandwidths, Comba has released updated firmware for our Class A Fiber DAS devices that allows for channel bandwidths of 75KHz. Utilizing a 75KHz channel bandwidth will result in group delay figure of 15usec maximum – which is well within the tolerances required for excellent call quality on P25 Phase II networks. This updated firmware is available directly from Comba and is available on Comba's portal which you can access here: Firmware Download

How can I commission the Public Safety CriticalPoint Fiber DAS on a P25 radio system which is non-trunked (no control channels available)?
Comba Public Safety Fiber DAS utilize control channel signal levels in P25 based trunked system networks as the means for monitoring and alarming for donor antenna malfunctions. It is rare – but there are cases where the network is NOT a trunked network; therefore, there are no control channels available for use in donor antenna monitoring and alarming. In these cases – Comba offers an easy to install/easy to use kit that includes all of the components necessary to provide the ability to monitor and alarm for donor antenna malfunction in non-trunked network applications.

These kits are available directly from Comba – following is a link to the specification sheet for the kit; the specification sheet also includes the part number and other information necessary to order the kit. Link: BIAS-T KIT FOR NON-TRUNKED RADIO SYSTEMS

CriticalPoint's Fiber DAS software report function doesn't work in a Chrome browser.
Solution: Download PDFs in Chrome

1. On your computer, open Chrome.
2. At the top right, click More Settings.
3. At the bottom, click Advanced.
4. Under "Privacy and security," click Content settings.
5. Near the bottom, click PDF documents.
6. Turn on Download PDF files instead of automatically opening them in Chrome.

Chrome will now download the generated Report.


Questions? Call 1-408-649-2638 or email This email address is being protected from spambots. You need JavaScript enabled to view it.