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Questions tagged [telephony]

For questions about telephony in relation to networking. For instance, you are setting up, designing or is having trouble with your IP telephony solution. Physical network installations in regards to telephony, eg. RJ11/RJ45 etc.

-1
votes
0answers
15 views

Phone cable categories [on hold]

I need to change the phone wires of my house because their are very old and broken. I know about network cables but I want to know which phone category is recommended for the interior of my house. I ...
7
votes
4answers
823 views

Why is the Ethernet Connection Symmetric?

I know that cable connection (DSL) is asymmetric, there is a certain bandwidth on the channel, and for a better user experience, they allocate a bigger portion to the downstream. I suppose Ethernet ...
1
vote
0answers
48 views

SIP message, Via, Call-ID and Contact headers [closed]

In a SIP message, how is the "Via" header set? If the value that appears in that header doesn't look correct, how can it be altered using Cisco command(s)? Same questions for the "Call-ID" header, ...
6
votes
3answers
1k views

Is QoS an issue for VOIP calls over the Internet? If not, why not?

I'm trying to decide whether I should buy SIP trunks from my ISP or a 3rd-party. As I understand it, it's important to maintain QoS on an internal network (i.e. prioritize VOIP traffic). Is this not ...
2
votes
2answers
643 views

What exactly is the local loop?

It would be crazy to have two transmission lines per every subscriber run from the subscriber to the ISP, do ISPs use a multiplexer then?On a cable network everyone is on the same line so multiplexing ...
2
votes
1answer
74 views

Migrating from an IP addressing scheme to another one?

I have been tasked to migrate one of my customer's IP telephony network from 192.168.11.0/24 IP addressing scheme to 172.27.72.0/23. My customer has deployed Cisco Call Manager and Cisco Unity ...
2
votes
2answers
151 views

Forward single DID number to sip trunk

I am stuck on a project and need help. I have setup a SIP trunk on Cisco 2900 router to another vendors call server which is based on asterisk(custom application). We have phones register with the ...
1
vote
1answer
109 views

How to terminate the 3 pairs coming from 66 block into suite for POTS line

ATT put a note on the 66 block for this telephone line that says "Ground this pair" and the note was on the blue/blue white pair. However the 2 pairs that are punched down on the 66 block are the ...
1
vote
1answer
353 views

Phone and PC network sharing one wifi bridge

We have a Cisco router from our T-mobile provider, two subnets on two ethernet ports: one subnet for PC data network, one subnet for IP phone network. The subnets have different IP addressing. As per ...
1
vote
1answer
55 views

PSTN Connection

So I have a CUCM sever setup and a few phones setup, I have a 1841 router as the default gateway for the network and I am looking at branching out from just internal extension calls. I have a VWIC-...
1
vote
1answer
164 views

Modem/device that can connect and route calls depending on type?

There are ways of allowing fax machines to share the same line as telephones and telephone answering devices. Back in the BBS days, a lot of people had dedicated phone lines for their BBS. A caller ...
0
votes
1answer
55 views

Would a pulse dial telephone affect ADSL reliability/speeds? [closed]

I have set up ADSL in a Spanish property that has a single pulse dial telephone. A DSL splitter has been used, and both the telephone and ADSL work. ADSL speed in this area is poor anyway, so its ...
3
votes
1answer
91 views

Working of a analog telephone - Basics

I am reading the following line from a book: The reasons that modems are so slow is that telephones were invented for carrying the human voice and the entire system has been carefully optimized for ...
1
vote
1answer
174 views

Configure switch in GNS3

Is there any way to configure a switch in GNS3?
1
vote
1answer
54 views

What is meant by Operator Specific Services (OSSs) in telecommunication?

Google search gives me definition of Value Added Services and other things, but not OSS's. I have read about OSS's here: The GSM service control function (gsmSCF) is a new entity that consists of ...
2
votes
2answers
93 views

Can you nest Private Branch Exchanges?

Say I have a PBX system and want to connect the outside line to another PBX unit (as an extension). And say I want to connect that to a larger PBX, etc... So, assuming that 9 is the outside line ...
2
votes
1answer
194 views

Wiring question at POTS DEMARC point

This is my first time using stack exchange. Let me give a brief backstory. I work at a company, we have multiple phone lines. One of the phone lines was cancelled but had a phone hooked up to it. I am ...
0
votes
1answer
74 views

How can I spoof a UK caller ID from the US? [closed]

I own several phone numbers in the United Kingdom that my UK customers can call to reach my business in the US. When we call UK customers from our US-based phones, we want the UK customers to see our ...
1
vote
1answer
56 views

Can cat6 be used as a 1:1 replacement for telephone cable?

Can cat6 be used as a 1:1 replacement for telephone cable ? Ive seen it done multiple times and its worked fine, but can it be considered a 1:1 replacement or are there some downsides of doing it ?
3
votes
1answer
397 views

Call is disconnected after huntstopped to another phone

We've been having an issue at the office with our Cisco CME. Here's the situation. Phone A (outside line) dials into the main line and after ~three rings the call is huntstopped to four other phones. ...
1
vote
1answer
207 views

Converting SIP to TDM?

We're looking to implement DID calling. Our local provider has indicated they can provide this via a SIP trunk, but cannot provide an E1. We also don't think they can provide an E1-over-SIP (where ...
1
vote
1answer
47 views

Smart switching calls in a company phone calls

We use VoIP phones in our company. Some people calls and each one connected to first free operator, and each people calls us once a week, we need one more option to make better experience for our ...
1
vote
1answer
247 views

ESI PBX LAN-only VoIP phone forwarding thru IPSec tunnel - remote router sees packets but not phone, doesn't forward

Okay, so we have an older X-Class ESI PBX system, an ESI IVX 128x FSIII [see below for link]. We have an LNC card installed in it, which allows for the use of up to 12 LAN-only VoIP phones. We have an ...
0
votes
1answer
315 views

Is it possible for ISPs to block part of VPN traffic, like UDP traffic only [closed]

My Question isn't about any carrier or ISP, as it might sound. It's about the technical aspect of internet censorship and needs networking experts to help. As you may know, some countries are blocking ...
1
vote
2answers
6k views

How are PBX extensions configured and how are outside lines obtained?

I'm trying to understand how to properly configure a PBX (Private Branch Exchange). I've stumbled into a few brick walls, and I feel like the answers to these should be obvious, but the Internet has ...
2
votes
2answers
73 views

PoE Query - IP Phones

My company have signed up for BT Business Broadband. We have IP Phones supplied by an external company. We have been led to believe that BT Business Broadband blocks IP Phones other than their own. Is ...
2
votes
1answer
502 views

Are DECT cordless phones interchangeable?

I would like to replace a Gigaset SL400 with a Panasonic KX-TPA50. Both phones are DECT. Since DECT is a standard, does that mean the new phone should just work with my current base station?
2
votes
1answer
474 views

How do I format an image for display on a Cisco SPA 303

In the manual it says I have to create a 128x48 bmp image with 1-bit per pixel, but when i upload it to the phone, it merely displays a full black image. I've tried: creating the image with gimp, ...
0
votes
1answer
342 views

Comparison between 2g and 3g in terms of PHYSICAL layer

I am doing a little research about comparison between 2g and 3g wireless communication technologies in terms of physical OSI layer. I want to focus especially coding differences. However, I couldn't ...
2
votes
2answers
98 views

Can several ISDN BRIs be mapped to a common phone number in north america?

We have several BRIs to provide a specialized service, which requires a specific type of hardware per BRI. We're struggling with offering incoming calls, as each of these lines has its own telephone ...
1
vote
1answer
124 views

FXO to GSM routing

I am new to VoIP so apologize if this is a dump question I want to accept a traditional telephone call (FXO) channel and based on the callers extension selection I want to switch the call to set of ...
1
vote
2answers
191 views

how to AS geographically apart are connected physically?

I am new to computer networking. One very simple question that comes to my mind is how two AS - geographically apart are connected with each other. For example, If I see the http://lg.bt.net/ BT ...
1
vote
2answers
1k views

What is the internal structure of a mobile phone call packet/datagram?

Coming from a Networking (IP/TCP/etc) background, I understand that a typical network packet looks something like the following: I further understand that VoIP packets typically do use the same ...
2
votes
3answers
1k views

Are voice and data transmitted differently?

Most mobile carriers' plans charge voice and data charged separately and differently. Consider in 2G,3G or 4G networks respectively: does it mean that voice and data are transmitted differently at ...
2
votes
5answers
4k views

Relationship between cellular networks and PSTN - especially in relation to the internet [closed]

I want to theoretically understand the general relationship between the PSTN (public switched telephone network), cellular networks, and the Internet. I understand that the PSTN provides the ...
0
votes
1answer
236 views

Configure E1 CAS signalling on a 2851 router

I have a 2851 VoIP router (CME) with four E1 ports. One port is configured as normal E1 PRI, and it is connected to PSTN. I want to configure another E1 port as a CAS signalling E1. I need to be ...
0
votes
3answers
136 views

Direct Phone Connection / Network Port over WAN [closed]

We have two office buildings connected by a WAN. Our primary office has a phone system that requires each handset to be connected to the PBX via cable (it is NOT VOIP compatible). We are setting up ...
2
votes
1answer
6k views

How to connect to a POTS line via a 66 block?

Today I had a POTS line installed to my 66 block/DEMARC. I need to hook-up a phone for this line for my boss. I'm assuming I can just wire the appropriate patch cable into the 66 block, patch it to ...
1
vote
1answer
2k views

Dedicated SBC really required for SIP trunking through a FortiGate 200B firewall?

I work at a school with a mid-sized ShoreTel deployment; two ShoreGear T1 trunk units and 15 ShoreGear 120/24 switches. We have a couple hundred IP phones and a couple hundred analog extensions (dorms)...
0
votes
1answer
500 views

Cell-phones and protocol-stack [closed]

When making a phone-call these day - the datastream is divided into packages, isnt it? But which protocol-stack is used then? VOIP is using tcp-ip but but what about cell-phones? For instance - the ...
4
votes
1answer
602 views

Can I Use Different Versions of CME and CUE

I am running CME 8.6 on a Cisco 2811. I would like to install NM-CUE and run CUE 7 with this. It this possible, even with a version mismatch?
2
votes
0answers
62 views

Is it possible to put one E0 voice signal directly into a STM1 frame

I've been going through STM1 frame structure recently. Is it possible to put a single E0(64kbps) voice channel directly into a stm1 frame or should it be put sequentially into a E1 and then to an E2 ...
2
votes
2answers
246 views

Why is the telephone network isochronous?

The definition page on Wiktionary for "Isochronous" offers this example of the word in a sentence: Their entire national telephone network is isochronous, with a clock distribution tree radiating ...
9
votes
1answer
8k views

What is “1 Erlang” for network data traffic?

I understand (or at least I believe I do) the concept of Erlang load unit when it is applied to voice communications. Voice communications occur in real-time and measured against real-time, so ...
12
votes
1answer
3k views

Point Of Presence vs. Central Office

What is the difference between these two (in distance and function)? I understand that a Central Office is a place where the ISP stores equipment that connects many clients. But the POP has a similar ...