Telephony
T1/PRI and analog lines
You don't have to wait for new lines or switch carriers to launch a contact center: your T1/PRI and analog POTS lines go to work as they are. Calls on them are routed to agents, recorded, and saved to the customer record. Analog phones in the warehouse, fax machines, and security alarm lines keep working. We pick the hardware, connect the lines, and, when you're ready, move numbers to SIP step by step – callers never notice the switch.
T1 line24 channelsin progressT1 linesecond, for growthon requestAnalog4 FXO linesin progressSIP trunknew numbersin progressFeatures
What we connect to your contact center
Examples
When it makes sense
Situations where companies connect T1/PRI and analog lines to their contact center.
The contact center launches on existing lines
A company still has two years left on its T1/PRI contract with the carrier. We connect the circuit to an interface card, and calls flow into the new contact center's queues. Alongside it, we add a SIP trunk and put new numbers on it, while the T1 stays as a backup until the contract ends.
- T1/PRI calls in your queues
- SIP trunk running in parallel
- T1 as a backup
NowT1 from carrierin progressStage 1SIP trunk in paralleltestStage 2new numbers over SIPscheduledT1until contract endsfailoverWarehouse and shop floor on analog phones
The warehouse and shop floor use simple analog phones, and replacing them makes no sense. They plug into the gateway's FXS ports, and each phone gets its own extension. A contact center agent transfers a customer's call to the warehouse the same way as to any colleague.
- Phones on FXS ports
- Their own extensions
- Transfers straight from the queue
Front deskanalogvia gatewayWarehouseanalogvia gatewayShop floorweatherproofvia gatewayTransferfrom queuerunningFax and security survive the move
Accounting receives documents by fax, and security and the elevators keep their own lines to reach the dispatcher. Once telephony moves to the platform, these lines plug into the gateway and work as before, with a daily check of their status.
- Accounting fax
- Alarm line and elevator phone
- Daily line checks
Faxreceiving documentsrunningSecuritypanic buttonline OKElevatorline to dispatcherline OKControlline checkdailyWe choose the right connection setup after inspecting your equipment on site.
How it works
Standards and hardware
Digital lines
T1/PRI, E1, J1, and BRI
A T1 has 24 channels; as a PRI, that's 23 voice channels plus one signaling channel (23B+D). E1 is the European equivalent with up to 30 calls, J1 is the Japanese variant, and ISDN BRI provides two channels. We confirm signaling with your carrier – typically ISDN PRI (Q.931).
- 23 calls on a PRI
- E1, J1, and BRI
- Signaling matched to your carrier
E1 / PRI30 channels per trunkyesT1, J1US and Japan standardsyesISDN BRI2 channelsyesSignalingQ.931, R2on requestAnalog
FXO and FXS ports
An FXO port takes a POTS line from your carrier, and an FXS port powers an analog phone or fax machine. Every port has echo cancellation, and calls are encoded in G.711 with no loss in quality, so they work for both recording and speech analytics.
- FXO – carrier line
- FXS – phone or fax
- Echo cancellation per port
FXOPSTN lineanswer and dialFXSanalog phoneas an extensionEcho cancellationon every portonCodecsG.711no lossesHardware
Interface card or gateway
If the platform server is on your premises, lines connect to a card installed right in it. If the platform runs in the cloud or the lines come into another building, a separate gateway terminates them and passes calls on over SIP. Sometimes we update the equipment firmware before connecting.
- Card in the platform server
- Gateway over SIP
- Firmware updates
Cardin platform serverPCI or PCIeGatewaystandalone deviceover SIPFirmwareupdateas neededPortsFXS, FXO, T1per projectSetup
How we connect existing lines
- 01SurveyWe list your lines, phones, and service numbers so nothing gets lost in the move.
- 02DesignWe size the hardware to your line count – no extra ports.
- 03CarrierWe confirm the circuit settings with your carrier in advance, so the connection works on the first try.
- 04InstallationWe install the hardware and configure ports and echo cancellation, so calls are echo-free.
- 05RoutingCalls from your existing lines are routed along with all the others, and analog phones get extensions.
- 06TestingWe test every line, call recording, the fax, and service numbers – neither employees nor customers should notice the move.
Requirements
What you'll need
- Lines
- T1/PRI, E1, J1, BRI, or analog
- Hardware
- Interface card or gateway
- Server
- Your own for a card; a gateway also works with the cloud
- Phones
- Any analog phones and fax machines
- Move to SIP
- Gradual, one number at a time
- Price
- You own the card or gateway; work is billed in support hours
Preparation
What to find out first
Q&A
Frequently asked questions
Can we launch a contact center on our existing lines?
You don't need to replace any carrier equipment: calls on these lines go into queues, get recorded, and open from the customer record.
How many calls can a T1/PRI handle?
A PRI carries up to 23 simultaneous calls (an E1 carries up to 30). If you need more, we add a second circuit or a SIP trunk alongside it.
Will our analog POTS lines work?
They will: each line becomes a separate number that takes and places calls.
Do we have to throw out our analog phones?
No. They get extensions, and agents can transfer calls to them.
Will the fax, security alarm, and elevator lines keep working?
They will: the numbers stay the same, and everything works as before.
Do we have to move to SIP?
Not necessarily. Your existing lines can work with the platform as long as you need, and you can move to SIP one number at a time when it makes financial sense.
What hardware will we need?
An interface card if the server is on your premises, or a gateway for the cloud or a remote building. We size the port count to your number of lines.
Can speech analytics review these calls?
It can, as long as the agent and the customer are recorded on separate tracks. T1/PRI and analog calls are recorded the same way as SIP calls.
Will this work for an international branch?
It will: we support E1, J1, and ISDN BRI and choose hardware for the right standard.
How do you get rid of echo on older lines?
Echo cancellation is turned on for every port. If echo persists, we troubleshoot the line together with your carrier.
How much does connecting existing lines cost?
There are no licenses. You buy the hardware, pay your carrier for the lines, and pay for setup under your support plan.
Glossary
Terms on this page
- SIP (Session Initiation Protocol)
- The protocol that sets up calls in IP telephony. Learn more →
- E1 – a digital trunk for phone lines
- A digital phone line that carries 30 calls into an office at once. Learn more →
- SIP trunk
- A phone line from the carrier over the internet instead of a wire. Learn more →
- Cloud deployment (cloud)
- The platform runs on the vendor's servers, and agents connect over the internet. Learn more →
- Customer record
- The screen of customer data an agent sees during a conversation. Learn more →
- Backup
- Data is regularly copied to a separate place so it can be restored if something goes wrong. Learn more →
- Speech analytics
- The system analyzes recorded calls automatically: topics, script adherence, customer emotions. Learn more →
- Call recording
- Calls are saved so they can be replayed and disputes settled. Learn more →
- Dual-channel recording
- Each speaker is recorded on a separate track. Learn more →
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