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Voice Services

Consolidate all your voice services — and deal with a single provider

Consider Call One your trusted telecommunications partner. We offer a wide range of voice services to meet your specific needs. Enjoy the benefits of multiple vendors, with the convenience of a single attentive provider and just one invoice.

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Business lines, often referred to as “Plain Old Telephone Service” or POTS lines, supply a single analog channel for telephones, modems and other devices.


PBX Trunks/Business Exchange Access Lines are central office lines used to connect client equipment, such as switchboards or consoles, with the Public Switched Telephone Network, also known as a PSTN.


Centrex is an alternative to premises-based PBX, multifunction and key systems. Centrex is a communication system that is tailored for each end-user. Centrex offers our clients robust call capabilities without the need for expensive onsite equipment.


Remote Call Forwarding (RCF) is a service that allows calls made to a specific number to be automatically forwarded to another number. RCF is commonly used to keep a phone number when moving office locations.


Integrated Services Digital Network (ISDN) Primary Rate Interface (PRI) is a standard, all-digital technology that gives you simultaneous, integrated voice and data capabilities. ISDN PRI is a solution for growing and large businesses that need a cost-effective system for clear voice and high-quality data traffic.

IISDN/PRI Features:

  • Caller ID name and number
  • Direct Inward Dial (DID) numbers
  • Directory listing
  • Failsafe routing
  • Remote call forward on demand
  • Virtual exchange


Integrated Services Digital Network (ISDN) Direct/Basic Rate Interface (BRI) is an affordable yet reliable form of high-speed, digital data communications. ISDN Direct/BRI provides the end-user with the ability to combine Circuit Switched Voice and Circuit Switched Data services over a single ISDN line.

ISDN Direct/BRI services require the use of an ISDN line (2B+D). The two 64 Kbps ‘B’ Channels are used to transmit any combination of Circuit Switched Voice & Circuit Switched Data Services. The ‘D’ Channel is used to carry signaling and user packet switched data.


Switched long distance calls are calls that connect to the PSTN via the prescribed inter-exchange carrier (PIC) assigned to the out-going telephone line.


Dedicated Outbound Long Distance service provides local access to the national network via a local loop circuit. Actual bandwidth and speed of circuits can vary from 56/64 Kbps or 1.544 Mbps up to 1 Gbps. Customers need long-distance routing equipment on their premises to accommodate dedicated long distance.


A Long Distance T1 is a 23- or 24-voice channel circuit used for outbound long distance calling and 800 # inbound calling that rides over T1 service. Inbound 800 # calls are set up using DNIS digits (numeric codes that are 4 to 10 digits long) that route 800 # traffic to a specific destination within the customer’s PBX equipment. Long Distance T1 is designed for businesses with high long distance call volumes.

Long Distance T1 Features:

  • High-capacity delivery at a low cost-per-minute rate
  • DNIS (Dialed Number Identification Service)
  • cSecurity and account codes
  • Toll-free and toll-free tailored routing


A toll-free number is a virtual address that points to one or more locations using intelligent network databases for routing criteria. The called party pays for the call. The toll-free number terminates to either switched or dedicated terminating addresses.

Switched access toll-free service provides both local and long distance service via the Public Switched Telephone Network (PSTN) over customers’ existing lines. A switched number is a 10-digit PSTN dialable number that points to a single physical location within the network.

Dedicated toll-free service is provided to a given site using single-purpose access circuits to deliver the toll-free call traffic only. A dedicated number is an internal identifier to the network that points to a single physical location.


Dynamic Integrated Circuits (IC) is a converged voice and data solution that utilizes your existing phone system or Private Branch Exchange (PBX) and is connected via a Primary Rate Interface (PRI), Digital Trunks, or Analog Lines to take advantage of VoIP-enabled capabilities and features.

With Dynamic IC, you fully integrate your data, voice, Internet and VPN (Virtual Private Network) services on a single connection. Data and voice services share all bandwidth with no artificial limits on the number of business lines.

Benefits of Dynamic Integrated Circuits:

  • Services combined on a single circuit for cost savings
  • Optimized voice lines and data bandwidth
  • Seamless communications across multiple locations
  • Scalable and secure
  • Unparalleled support 24/7


Voice over Internet Protocol (Voice over IP, VoIP) is a series of Internet technologies, communication protocols and transmission technologies for delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks such as the Internet.

Business VoIP Features:

  • Directory listing
  • Fully managed router
  • Session based
  • Voice compression enabled


SIP Trunking is a VoIP solution based on Session Initiation Protocol (SIP). This solution allows ITSP (Internet Telephony Service Providers) to give voice services and unified communication via IP access to clients equipped with a private infrastructure generally based on IP-PBX (Private Branch Exchange) technology in IP).

SIP Features:

  • Concurrent call sessions
  • Direct Inward Dial (DID) numbers
  • National and international availability of local numbers
  • Availability in more than 90% of domestic local markets
  • Long distance domestic and international services supported
  • International toll-free private dialing plans supported
  • 911 emergency services
  • Directory services and Caller ID with name


Hosted VoIP is a solution that uses the cloud to help businesses dramatically reduce costs, utilize enhanced IP telephony features, and simplify the management of communications across your enterprise. This solution includes such features as local and long distance calling, enterprise-wide HD voice and video, network services, IP phone sets, live voice quality monitoring and redundancy.

Get the voice services you need

Because Call One is the Suburban Purchasing Cooperative’s preferred provider, we accepted their offer to audit our phone bills. When we learned how much we could save, without having to switch from the AT&T infrastructure, we moved to Call One service right away. For over 5 years we’ve benefitted from their amazing customer service and their dedication to keeping us informed of any additional savings they can offer.

Mark Bologa, Executive Director,
DuPage Mayors and Managers Conference