16

What is the difference between this two (in distance and function). Short answer: Distances - not very much, these days Function - Basic / Enhanced 911 is still processed through the Central Office; however other CLECs can trunk customers' 911 calls back to the Public Service Answering Point (PSAP) via the local Central Office... I also think Intrado has ...


12

Background An Erlang measures load on a Circuit-Switched link. Quoting Russ Rowlett's page: The erlang is a dimensionless "unit" representing a traffic density of one call-second per second (or one call-hour per hour, etc.). The classical definition of an Erlang was developed in the early 1900s by Professor A.K. Erlang. Erlang's definition does not ...


12

The very first Ethernet standards were designed for using a single, shared coax wire. There's no benefit in making the connection asymmetric in any way. Additionally, network nodes are generally viewed as equal peers from the technology design perspective (in contrast to specific network design). There's simply no motive in making a general-purpose network ...


9

Q: Why is ethernet symmetric (when compared to ADSL's asymmetry). A: This is best explained by looking the technical reason for ADSL's asymmetry. Quoting directly from wikipedia: There are both technical and marketing reasons why ADSL is in many places the most common type offered to home users. On the technical side, there is likely to be more ...


8

VoIP over the public Internet can be a problem, but it usually works good enough, most of the time, although there can be times where it sucks. Most ISPs have extra cost features where they will honor some of your QoS markings and policies. (I know Verizon Business, among others, has some specific packages for QoS, and you may need to adjust your policies ...


7

Is QoS an issue for VOIP calls over the Internet? Sometimes. The answer why is related to the extinction of these objects: (for people born after the year 2000, that's a phone booth) Short answer: QoS is only an issue if the customer thinks it's important enough to pay for. Long Answer: Q&A it's important to maintain QoS on an internal network (...


7

As simply as possible, telephone calls are routed across a network of switches which are interconnected using trunks. There are interconnect points for different operators/carriers' switches. Since not every carrier is connected to all other carriers, call routing may pass through intermediate carriers until reaching its destination. The above applies for ...


5

Each B-channel has a SPID (circuit ID). It doesn't have to have anything at all to do with the PSTN phone number. Many LECs in the US assign the two together, but nothing in the switch requires this. Individual lines can be mapped to a "hunt group" with a single pilot number, and/or each line can be programmed to roll forward to the next ("rotary"). (Good ...


5

What is Local Loop? The portion of the telephone system that connects your home or office to the nearest central office (CO) of your local telco. The wiring used in the local loop is usually unshielded twisted-pair (UTP) cabling, the transmission method is analog transmission, and the maximum distance from the telco’s CO to the subscriber’s customer ...


5

Ethernet is a local area network technology, and it was designed with no assumption that traffic will be higher in one direction than the other. It was developed long before the web or Internet was available.


5

The cabling for ADSL uses telephone grade cabling and upstream and downstream traffic share the same copper pair. As there is limited bandwidth, the designers chose to give the downstream more capacity to make more efficient use of the bandwidth, something that fits the usage patterns of home users. ADSL was designed for a specific use case – to connect ...


5

SONET is a physical layer protocol (layer-1). You need a datalink layer protocol (layer-2) to handle framing. That was originally ATM, because that was one of the dominant L2's used by carrier networks. (vs. frame relay, ATM easily mixes voice and data.) IP (layer-3) "directly" over SONET still needs framing. Packet-over-SONET (POS) uses PPP (...


4

The black and yellow pair should be terminated on the pins just to the right of where the phone company terminated the pair. You can look at the pair above the pair you want and see someone has terminated something right above where you want to terminate. That's called a 66 block and it has 50 rows of terminals by four columns. Each row in the left two ...


4

Mixing versions like this, depending on which version of CME and CUE you are using, will work in some instances. In your particular case however, it appears that the answer is no. CME 8.6 will only work with CUE versions 7.3, 7.4, 8.5, and 8.6. Since you're talking about a plain NM-CUE in a 2811, that module will only support up to CUE version 7.0. Your ...


4

Yes, this is certainly possible. You can install a E1/PRI VWIC in a Cisco router and the Cisco router can act as a gateway between TDM and SIP. There are of course solutions by other vendors. This is a fairly broad subject, so you will need to read up on it, but it is defiantly possible.


4

There is the Public Switched Telephone Network (PSTN) that connects calls between wired (fixed line) and wireless telephony subscribers (GSM is just the 2nd generation wireless telephony system, and there are others). Unlike packet-switched networks like the Internet, the PSTN is circuit-switched. For purposes of call routing, there are three pieces of the ...


3

Your question: We have been led to believe that BT Business Broadband blocks IP Phones other than their own. Is this true? is off topic here. You will need to ask BT, but it doesn't matter if you are not going to send VoIP traffic over the BT network (outside of your network). If your phones need PoE, they must be directly connected to a PoE switch, ...


3

First of all, does a PBX require its own power supply? A PBX does require it's own power, and you must have batteries or a UPS in the event of a power outage. If your PBX is Centrex (hosted at the exchange), will the telephone company supply power to your PBX in an outage? Most telcos will insist on and install a UPS for any of their equipment which ...


3

(Assuming North America as our venue) The voice part of a mobile connection, like non-mobile ISDN voice network, has been circuit switched up until LTE. LTE is only packet switched, so either Voice over LTE is used (sort of like VoIP) or voice is sent circuit switched separately from the packet switched data. It turns out that right now, that for most ...


3

It will work. Keep in mind this to learn why: 1 - A LAN is a single broadcast domain and single collision domain. Collision Domain: It means that a collision will be sensed by all the devices in the network. Broadcast Domain: A broadcast frame will be heard by all the devices in the network. 2 - A layer 2 switch (also a bridge) is a single broadcast ...


3

The local loop is your home's or business's dedicated connection to the nearest concentrator (often within a Point of Presence (PoP)). The concentrator basically multiplexes many connections to a single or very few connections and is connected to the ISPs core network, possibly via more concentrators. This follows the general paradigm of the network idea ...


3

SONET, or rather the synchronous digital hierarchy it's running on, requires very tight clock coupling across the whole structure. In order to stay within the sub-millisecond tolerances, there's no other way than with atomic clocks. Sharing a central clock wouldn't work due to the inherent limitation of the speed of light, which covers just 300 km in one ms (...


2

It's normal for 2G to still go over SDH/PDH networks even if many mobile carriers are upgrading them to ethernet networks. If the same carrier has 3G and 4G technologies thay would most likley be running on ethernet networks or at least the latter. So maintaining two different networks would be expensive and supporting PDH/SDH would probably be more ...


2

Actually, it shows that Telstra Global (which as the name implies, has a global presence) is connected to Level 3 (which also has a global presence). If you look at the round-trip times, you'll notice that hops 3 and 4 are about 150 ms away from Sydney (hops 1 and 2), so most certainly in California, close to hop 5 (which is clearly identified as being in ...


2

A PBX is typically implemented in organizations that have many users who each require a telephone. They typically dial one another via 4 digit dialing. If a PBX phone user wants to call and order a pizza, they typically dial 9, for example, to obtain an outside line, then dial the public (PSTN) phone number of the pizza place. A single phone line is ...


2

Where do you live? If it's US they aren't allowed to do that legally. All you'll have to do is find a SIP provider and have your Call Manager of whatever flavor register to it. You may run into QoS issues using just standard ISP broadband though with latency and jitter. PoE is industry standard so almost any PoE switch will be able to power it, make sure ...


2

DECT 6.0 is a standard, but many vendors' implementations are proprietary. See Digital Enhanced Cordless Telecommunications: DECT 6.0 products do not support "GAP"; therefore, phones of differing brands are not guaranteed to work together. For example, a GE 28105EE1 DECT 6.0 headset will not receive calls if registered to a Uniden base unit. Also, ...


2

Typically in order to handle this type of scenario, you need to add an ACD (Automatic Call Distribution) component to your telephony solution, and tie it into your CRM. The idea is that your CRM tool contains information that will allow the routing to be performed, such as whether a given caller has a primary assigned service rep, or simply who handled that ...


2

A higher category cable can be used for a lower category cable. Ordinary telephone cable is Category-3 cable. The downside is that simply replacing one category cable for another can be very misleading. Simply having cable at a category is meaningless. All the cable components (connectors, patch panels, etc.) must all be the same category, and they must ...


2

I would say it is some type of electrical grease, to keep moisture out. Maybe try trace the pair from the block you are wanting to connect into, trace that pair back to the cable coming into the distribution block, cut it out from back of block and use scotch locks, or soemthing similar, to crimp your pair to the POTS pair. You could get into trouble by to ...


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