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PBX Infrastructure
A plethora of hardware (PBXs, key systems, processor modules, line modules), software, and signaling protocols (Primary Rate Interface [PRI], Q.SIG, and channel-associated signaling [CAS]) exist to facilitate call control. For interaction or replacement of these systems with IP telephony systems to take place, you must start preparation and planning early in the deployment cycle. This section takes you through the first step of surveying the components that exist to facilitate this initial planning and helps you to determine an overall level of effort or risk given the impending deployment of IP telephony. Use the questions provided in Table C-1to gather information on existing PBX deployments at your customer network.
| No. | Question | Answer | |
|---|---|---|---|
| Basic PBX Information | |||
| 1 | What are the site details and location of the PBX? | Location Name:Site Address:City/State/ZIP:PBX Room No.:Floor: | |
| 2 | Who is the PBX contact representative at this site? | Name:Phone:E-Mail: | |
| 3 | Is this PBX leased or owned? If it is leased, what is the lease expiration date? |  Leased OwnedLease Expiration Date: | |
| 4 | If the vendor maintains the PBX, what is the vendor contact information? | Name:Phone:Alternate Phone:E-Mail:Pager: | |
| 5 | Who are the vendors and their corresponding models of the PBX at this site? | Location :Vendor:Model:SW Release:Signaling Protocol:Location:Vendor:Model:SW Release:Signaling Protocol: | |
| 6 | Are you planning to replace this PBX or integrate it with the IPT system? | Replace Integrate | |
| 7 | If you are replacing the PBX, do you want to do a flash-cut migration to the new IPT system or a phased migration? | Flash-Cut Migration Phased Migration | |
| 8 | If you plan to do a phased migration, what are your plans? | ||
| 9 | What link types provide network-side (trunk) access to the PSTN? | Digital Analog | |
| 10 | What is the existing PRI/T1/E1 trunk capacity, and how many trunks are in use? | Capacity:Trunks Used: | |
| 11 | What is the existing analog trunk capacity and how many trunks are in use? | Capacity:Trunks Used: | |
| 12 | What is the existing recEive and transMit (E&M) trunk capacity, and how many trunks are in use? | Capacity:Trunks Used: | |
| 13 | What are the signaling protocols that connect to the PSTN?If analog is used, is it Foreign Exchange Office (FXO), Foreign Exchange Station (FXS), E&M, or Direct Inward Dial (DID)? | PRI E1R2 BRI Analog SS7 | |
| Voice Circuit Characteristics | |||
| 14 | What is the name of the service provider, and what is the circuit ID? | Service Provider:Circuit ID: | |
| 15 | What are the framing type, encoding type, and D-channel locations? | Framing | ESF SF G.704 |
| Line Code | B8ZS AMI CRC-4 HDB3 | ||
| D-Channel Location | Ch24 Ch1 | ||
| 16 | What is the central office switch type? | DMS 100 DMS 250 DMS 500 5ESS NI2 Other | |
| 17 | What is the trunk's hunt sequence? | Top Down Bottom Up Least Idle | |
| 18 | How many digits are out-pulsed? | Digits: | |
| PBX Interconnection Between Sites | |||
| 19 | Is this PBX interconnected to other PBXs at other sites? | Yes No | |
| 20 | What link type interconnects the PBXs? | Q.SIG BC Q.SIG NA Q.SIG GF Other | |
| 21 | Are any special or proprietary PBX features enabled on these links?If yes, describe them in the "Notes/Comments" section. | Yes No | |
| PBX IntegrationHardware Specifications | |||
| 22 | Are there available ports on the PBX for connecting to Cisco voice gateways? | Yes No | |
| 23 | What signaling type is available on the ports to communicate with Cisco voice gateways? | PRI E1 BRI FXO E&M | |
| PBX High Availability and Traffic Statistics | |||
| 24 | Is redundancy deployed where possible in the PBXs? | Yes No | |
| 25 | What are the busy hour and busy hour traffic at this location? | Busy Hour:No. of Calls: | |
| 26 | What percentage of total calls are the fax calls? | ||
| PBX Support for Emergency Call Routing and Advanced Features | |||
| 27 | (Specific to U.S. and Canada) Do all the PSTN trunks support 911 emergency call routing and send the caller information to the public safety answering point (PSAP)? | Yes No | |
| 28 | Does your existing PBX system support E911 functionality? If yes, explain in the "Notes/Comments" section how this functionality is provided in the PBX. | Yes No | |
| 29 | (Specific to U.S. and Canada) Does your state or province regulation require you to comply with E911 regulations? | Yes No | |
| 30 | Are advanced carrier services, such as AT&T's Software Defined Network (SDN), in use? | Yes No | |
| 31 | What is the range of extensions that is currently configured on this PBX? | Use the "Notes/Comments" section to provide the list of configured extensions. | |
| 32 | What are the DID number ranges assigned to this site, and over which trunk interface are these DIDs delivered? | DID delivered via: | PRI E1/T1 Analog E&M |
Notes/Comments
You have to collect the information given in Table C-1 for each site. You will use the information that you collect through this table during the design and implementation of the IPT project. During the design and implementation phase, configuration changes are required on the PBX systems to migrate the users to the IPT system. The PBX representatives are the personnel who have authority to make these configuration changes on the PBX. Provide details such as how and when you will move users and Public Switched Telephone Network (PSTN) trunks from the legacy PBX to the new IPT system.
