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Community Member

Recommended Voice Gateway Router

In order to support 161 T1/PRI Channels and 144 T1 CAS/E&M Channels what would be my best options keeping in mind 911 Calls as well. I am leaning towards (4) Cisco 3845 routers in the following Configurations.

First 3845 router will have 4-port PRI T1s, and 2-port FXO card for 911 backup.


Second 3845 router will have 4-port PRI T1s, and 2-port FXO card for 911 backup.


Third 3845 router will have 3-port CAS T1s.


Fourth 3845 router will have 3-port CAS T1s.


Re: Recommended Voice Gateway Router


How many locations (buildings) with different E911 reporting addresses do you serve? What is your current device load in CCM?

What you have will function well, keeping in mind allocation of DSP resources for transcoding and conferencing, etc.

If you already have routers connecting remote sites to the core (unsure if this is your configuration) you may also consider router FXO for 911 with two ws-x6608 voice gateways in 6000 chassis for PRI termination. This allows diversity between the gateways for maintenance, etc. If all phones are at one E911 reporting address the 6608s will provide that to the PSAP and the only need for FXO would be SRST.

Again, this depends on your environment and what hardware you currently have.

Take a look at the SRND for CCM (this one is for v5.0) regarding gateways, if you have not done so already.

Hope that helps.


Community Member

Re: Recommended Voice Gateway Router

Currently, they have legacy PBXs, with basic 911. They are not looking into E911 even they should because it is a huge manufacturing campus with higher possibilities of accidents. Luckily I have a choice to recommemnd that best fits for them. IP/WAN routers are managed by their ISP and we have no control. What I will end up doing connecting my Voice/Gateway router to ISP managed router for IP/WAN connectivity via Ethernet. WAN router will be configured for QOS by ISP.

It is a manufacturing corporation so Accidents do happen frequently that is why they need a Voice Gateway Router that is 100% reliable when it comes to calling 911.

They will be looking into couple of options. E911 or Security Desk Help type of solution in future.


Re: Recommended Voice Gateway Router

Thanks, Abbas.

You should check with the local PSAP and E911 standards as there may be legislation in place (or on the horizon) that would mandate E911 compliance for new installs of PBX/VoIP.

You can look here for more information on the regulations:

If E911 compliance is necessary due to the campus and building sizes it may be wise to research Cisco's Emergency Responder. The advantage there is not only management of reporting location to the PSAP by switch port, but also on-site alerts to anyone trained in EMS (internal security staff or building manager) and reporting for calls placed to the emergency number, whether it be 911 in the US or other numbers in other countries. We now use analog lines only for SRST, as CER sends the correct address information through the PRIs for the entire campus.

Here's the admin guide for CER 1.2(3) for reference:

A side note: as a county we provide emergency services to millions of residents (sheriff's department and hospital within our organization) and were very careful when deploying our own VoIP solution. We ended up deploying CER in our campus due to square footage of buildings and floors in large structures as it was mandated we comply with E911 by 1-1-2006.

Hope that helps out.



Re: Recommended Voice Gateway Router

if you have the option of using a CAT 6500 series, then 2 x 6608 T1/E1/PRI blades will suffice providing upto 184 PRI channels and 192 CAS channels.

a 6624 could supply FXOs.

(just another option, thinking out loud here; it's what i use for my datacenters)


Re: Recommended Voice Gateway Router

Here is another option if you are using a CAT 6500 series, instead of using the 6608 blade, use a Cisco Media Module. It will hold 3 each 6-port T-1/PRI cards plus an internal card to boost the DSP resources. The nice thing about the CMM is that it uses IOS where the 6608 uses CAT OS, but it is a little harder to configure.


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