PX24X: Large Capacity Hybrid IP PBX

PX24X in Brief

With a total capacity of 448 TDM ports that allow connections to Basic and Primary Rate ISDN terminal equipment, analog telephone and fax, Telesis digital set, and hundreds of H.323 and  SIP entities such as terminals, gateways, gatekeepers, and registrars for VoIP calls, the Telesis PX24X Hybrid IP PBX is the perfect solution if you are looking into expanding or updating an existing telecommunications network, migrating to the IP Telephony or building a network that is ready for the future. The TDM trunks support a wide range of signaling types, including SS No. 7, V5.2, DSS1 Euro ISDN, QSIG, R1, R2, CL-1B, OCL-1B, TCL-1B, SL/ZSL, SLM, and other CAS signaling. The built-in 10/100 BaseT ethernet interface supports H.323, SIP and Telesis xSIP (eXtended SIP) protocols at the same time. The PX24X is capable of routing TDM calls to VoIP calls and vice versa. 

The Telesis PX24X can be configured as a Hybrid IP PBX, PBX, rural exchange, signaling converter, V5.2 AN/LE or channel bank.

The Telesis PX24X has a modular mechanical structure. The installation of the system or expanding an already operating one by adding subscriber and/or trunk line interfaces is simple and fast.

Telesis PX24X with modular mechanical structure. Easy capacity expansion.

PX24X as a Hybrid IP PBX Business Phone System

The Telesis PX24X Hybrid IP PBX Business Phone System offers significant cost and performance advantages. The obvious advantage of IP Telephony is cost savings. Sending packets of data via an internet network is cheaper than making voice calls over a traditional circuit switched telephone network. The PX24X combines VoIP technology, TDM technology, and Telephony features altogether. Telesis PX24X IP PBX systems are engineered to: 

• provide quality of voice over internet
• secure calls
• provide IP-TDM gateway capability
• provide softswitch capability
• include integrated H.323 gatekeeper
• include integrated SIP registrar
• include integrated xSIP registrar
• include integrated FTP client to upload records to an FTP server
• manage the traffic efficiently
• provide alternate TDM routes if IP trunk calls fail due to network unavailability
• support numerous system and user features
• be scalable for future expansions
• have open architecture for future implementations 

Big savings can be achieved by using the Telesis PX24X Hybrid IP PBX Business Phone System to:

• bridge distant corporate offices
• access long distance call operator rather than paying high traditional call charges

Another advantage of the Telesis PX24X Hybrid IP PBX Business Phone System system is to increase the productivity of employees. Employees would be able to communicate without incurring greater communication costs in the process.

The Telesis PX24X Hybrid IP PBX Business Phone System is equipped with well-known industry standard codecs for high quality communication as well as low bandwidth usage. It is capable of supporting multiple codecs and ready for adding more as technology emerges and popularity changes. Another key technical requirement for the VoIP quality is the echo cancellation. The echo canceler of the Telesis PX24X IP PBX is AT&T certified and exceeding G.168:2002 requirements. It is better than industry standard cancelers under the most important and difficult conditions like double-talk and the presence of background noise.

Considering the security issue, the Telesis PX24X Hybrid IP PBX Business Phone System provides greater protection than traditional phone systems. Furthermore, the ability to encrypt voice via IP call by using 256 bit AES (Advanced Encryption Standard) provides an advantage for security compared to existing telephone systems.

Various local and remote users of the PX24X, which can be IP or TDM.

System Phones, System and User Services

DTS821 is an executive digital telephone set for the PX24X IP PBX for the comfort of the user. The DTS821 has easy-to-use access menu keys and numerous dedicated keys for various telephony tasks and personnel settings. It has a large backlighted graphic LCD. DTS821 is connected and powered by a single pair of wires. The set handles multiple calls simultaneously, such as receiving a new call while keeping another on hold. Remarkable features are:

• easy-recording (single key press) the conversation bi-directionally (both calling and called party voices)
• access to missed calls list
• access to dialed numbers list
• access to incoming calls list . access to directory
• playing, deleting voice messages and recorded conversations
• setting volume
• setting ringer volume
• selecting ringer melody
• programming function keys
• programming quick access keys
• setting call forward unconditional
• setting call forward busy
• setting call forward no-reply
• setting hotline
• activating call waiting
• activating do not disturb
• activating wake-up (reminder) service
• observing firmware version
• deflecting calls
• activating call back
• holding calls on
• retrieving calls
• transferring calls
• tracing transferred calls (up to 4 calls)
• activating conference

DTS821 Digital Phone in gray color

Two other digital telephones are DTS821S and DTS200S. DTS821S is the digital telephone set offering advanced telephony tasks similar to these of the DTS821 executive set. Users without need of many quick access keys may choose the DTS821S and get the benefits of the Telesis PX24X Hybrid IP PBX Business Phone Systems. DTS200S is a good match for economy and utility. DTS200S offers the comfort of digital voice quality as well as numerous value added services like one-key-touch personal conversation recording.

DTS821S Digital Phone in white color

DTS200S Digital Phone in white color

The Telesis PX24X Hybrid IP PBX Business Phone System provides hundreds system features, system parameters, and user services. If it is desired, these may be activated or deactivated. With these programmable features and services, the PX24X IP PBX make traffic management highly efficient and versatile.  The convenience of dealing with all-in-one system software Xymphony allows the user to support as many features as desired, up to the maximum capacity.  Another aspect of the PX24X IP PBX system`s software is an advanced algorithm for creating routing tables. 

Many of the user services are applicable for SIP calls with using the basic SIP supplementary services such as Invite (call hold), call forward and call transfer (with refer method). Similarly, these are also applicable for H.323 calls with using the basic H.450 supplementary services.

Furthermore, Telesis proprietary xSIP (eXtended SIP) protocol allows value added services of the DTS821 digital telephone sets also to be functional over IP.

ITS821 IP Phone and XPhone IP Softphone (PC edition) have easy-to-use access menu keys and numerous dedicated keys for various telephony tasks within the PX24X Hybrid IP PBX System. 

XPhone IP Softphone (Mobile edition) for Pocket PC Phone and Smartphone.

Another challenging feature available with PX24X Hybrid IP PBX Business Phone System is the Telesis WebPhone. It is a SIP softphone or client applet hosted in the PX24X. The applet can be run from any java enabled web browser. Since it is a standard java applet, no software installation is required or no plugin is installed. The applet is just loaded temporarily onto the client`s browser. It can be used wherever is an access to the Internet. A web browser, a microphone, and a headset are sufficient to make calls. 

Telesis WebPhone Main Page for the Browser

Telesis WebPhone is completely an independent application. It works with all main browsers such as Internet Explorer, Mozilla Firefox, Opera, Google Chrome, or Safari. The feature empowers web sites of Telesis PX24X owners. Deploying the webphone on a web site is just an issue of placing a simple html link to the hosting Telesis PX24X system.

For ensuring the easy and fast programming of the PX24X IP PBX, each programmable parameter is set to a default value. The standard default values are carefully selected and optimized for a wide range of customers` requirements. Thus, the flexibility does not bring a complexity.

High quality PX24X cabinet. Optional 19inch subrack adapters allow PX24X Hybrid IP PBX Systems to be also mounted into industry-standard racks.,

Utilities for System Owners and Administrators

XTools is a next generation utility software developed by Telesis A.S. to be used with Telesis PX24X Hybrid IP PBX Systems. Moreover, it is freeware.

Experts as well as novices may get the benefits of XTools. An easy to use and flexible toolkit allows system owners and administrators:

• to discover Xymphony compatible Telesis equipment in the local network and edit their settings
• to trace and capture telephony events and call control messages of selected TDM users
• to download CMDR (Call message detail recording) records
• to download automatic voice recordings 
• to generate formatted CMDR reports 
• to trace, select, view or backup CMDR database
• to trace, select or play voice recordings 

Some Other Applications with the PX24X

PX24X as a V5.2 Access Network (AN) Equipment

The term AN (access network) refers to the network between the local exchange (or Central Office) and the subscriber. In many countries, this network is still predominantly made up of the copper-cable-based point-to-point connections. However, conventional point-to-point copper cabling has some limitations:

• It offers limited bandwidth, which is difficult to overcome.
• Inflexibility: both in time and types of service provided.
• Due to star topology (from the exchange to the subscriber), reliability is limited.
• Installation time is long.
• It is maintenance intensive due to possible cable damage and thus costly.
• Largely passive, making it difficult to manage.
• Loop length limitations( ~ 10 km ).
• Uneconomical in remote, isolated areas with low telephone densities.
• Prone to electromagnetic interference.

To overcome the above-mentioned issues, several vendors developed AN (access network) technologies, almost all which support the V5.2 protocol in connecting to the voice-switching Local Exchanges.

Telesis PX24X is an ideal V5.2 Access Network equipment for analog telephone access (with Caller ID support). At its maximum capacity, the PX24X AN can have up to four E1 interfaces with V5.2 protocol. Switching is actively done on the local exchange (LE) side, the number of bearer channels between the LE and the PX24X AN should be planned in accordance with the expected telephone traffic. Erlang loss formula could be used as a service quality target. To illustrate, through a 60-channel (2 x E1) capacity V5.2 interface, total erlang traffic capacity is 44.75, with a lost-call probability of 0.005 at random traffic. Consequently, for a 250-subscriber capacity PX24X AN with a 60-channel V5.2 interface, erlang per subscriber is almost 0.2.

PX24X as a Channel Bank

Telesis PX24X is ideal for highly advanced but cost-effective channel bank solutions. The PX24X is an intelligent channel bank that can interface with E1 ports of any switch, VoIP server, PBX to interconnect FXS, FXO, and E&M. Signaling types and protocols supported by the PX24X`s E1 interfaces are:

• Single-bit E&M emulation
• Two-bit ITU-T R1
• Two-bit ITU-T R2
• Many variations of signaling types (such as CL-1B, OCL-1B, TCL-1B, SL/ZSL, SLM) widely employed in CIS countries

• DSS1 (EuroISDN in the TE direction)
• DSS1 (EuroISDN in the NT direction)
• ECMA QSIG (in the TE direction)
• ECMA QSIG (in the NT direction)
• ITU-T and ETSI Signaling System No.7 ISUP

At its maximum capacity, the PX24X Channel Bank can have up to four E1 interfaces with 120 voice channels to interconnect FXS, FXO, and E&M ports. For various capacity requirements, it may be configured as:

• four E1s : 120 voice channels
• three E1s : 90 voice channels
• two E1s : 60 voice channels
• one E1 : 30 voice channels

• Scalability from one to four E1 interfaces
• Fractional or full E1
• Clock source could be configured as internal or external
• Scalability from 30 to 120 voice channels
• Supports various signaling types and protocols
• Mixed use of FXS, FXO, and E&M ports
• Modular architecture allowing custom-configured channel banks to fit the exact requirements
• Address transmission as Overlap or Enbloc 
• Internal power supply

• 16-channel FXS card (with Caller ID)
• 8-channel FXO card
• 4-channel 2-wire E&M card
• 4-channel 4-wire E&M card

PX24X as a Rural Exchange (Rural Switch)

As a rural exchange, the Telesis PX24X serves as a service switching point (SSP). The PX24X is stored-program controlled. SSP and routing functions are integral parts of its operating system. The PX24X rural exchange can be connected to several adjacent SSP and STP switches. 

The PX24X rural exchange also supports many signaling systems of legacy PSTN networks. The PX24X has a call-completion success rate of over 99.999% at 24,000 BHCA (Busy Hour Call Attempts).

Key features of the Telesis PX24X rural exchange are:

• Scalability from one to four E1 interfaces to connect to adjacent exchanges
• SSP and STP support
• Capacity for up to 448 subscribers with long loop drive
• Caller ID (according to ETSI FSK standards) for analog subscribers
• Numerous digital and analog signaling protocols
• Detailed records of originating and terminating calls
• Traffic measurement
• Monitoring and analysis of signaling
• Numerous subscriber services

Technical Specifications

General
Operational software	Xymphony PX24X
Maintenance and administration	Over IP
Operating voltage	220 VAC,48 VDC
CPU Type	High speed DSPs
Switching Matrix	512 x 512
Analog subscriber loop impedance	3,000 ohms
Ethernet interface	10/100 BaseT
Caller ID ETSI FSK modem	Yes
Integrated CMDR buffer	Yes
Integrated DVR (Digital Voice Recorder)	Yes
DVR recording capacity	100 hours
DVR recording channels	4 (up to 44 with licensing)
DVR playing channels	4 (up to 44 with licensing)
Xymphony API server	Yes
FTP client	Yes
Conference hardware	Yes
DTMF transceivers	Yes
MFR1 transceivers, ITU-T Q.320	Yes
MFCR2 transceivers, ITU-T Q.441	Yes
HDLC transceivers	Yes
ANI transceivers	Yes
Pulse shuttle (R1.5) transceivers	Yes
Real-time charging	Yes
12 or 16kHz charge pulse detectors	Yes
Polarity reversal detectors	Yes
A-Party analysis	Yes
B-Party analysis	Yes
Subscriber services	Yes
Credited subscribers	Yes
Remote access	Yes
Signaling interworking	Yes
Programmable tones	Yes
Programmable ring melodies	Yes
Applications
Rural switch	Yes
V5.2 Access Network / Local Exchange	Yes
Signaling (protocol) converter	Yes
SSP, Service Switching Point for SS7	Yes
STP, Signal Transfer Point for SS7	Yes
PBX	Yes
Hybrid IP PBX	Yes
Interfaces (max.)
Analog subscribers	448
Digital subscribers	64
Analog DC loop trunks	224
Analog E&M (two- or four-wire)	112
RDTT (Ring Down Tie Trunk, local battery)	224
BRI ISDN S0	4
BRI ISDN Uk0 (Line code 2B1Q)	4
PRI ISDN	4
E1 interfaces (ITU-T G.703)	4
SIP user agents	512
H.323 endpoints	512
Telesis xSIP users	96
TDM Signaling
Dial-pulse dialing from analog subscribers	Yes
Dial-pulse dialing to analog trunks	Yes
DTMF dialing from analog subscribers	Yes
DTMF dialing to analog trunks	Yes
Caller ID transmission on analog subscribers	Yes
Caller ID detection on analog trunks	Yes
12 or 16kHz charge pulse detection on analog trunks	Yes
Polarity reversal detection on analog trunks	Yes
Pulsed line/pulsed address on E&M	Yes
Continuous line/DTMF address on E&M	Yes
Single-bit pulsed line signaling types on E1	Yes
Single-bit continuous line signaling on E1	Yes
MFR1 signaling on E&M	Yes
MFCR2 signaling on E&M	Yes
MFR1 signaling on E1	Yes
MFCR2 signaling on E1	Yes
ISDN (Euro ISDN, DSS1), ETSI EN 300 403	Yes
ISDN Supplementary services: 3PTY, AOC, CCBS, CCNR, CFU, CFNR, CLIP, CLIR, COLP, COLR, ECT, DDI, HOLD, MCID, MSN, UUS	Yes
ISDN (QSIG), ECMA-143 PISN	Yes
V5.2 LE protocol, ETSI EN 300 347	Version 2
V5.2 AN protocol, ETSI EN 300 347	Version 2
SS7 ISUP (CCS no.7), ETSI EN 300 356, ITU-T	Yes
CIS Countries - Russia
Local  trunks SL, Connection line CL	Yes
Toll-connecting trunks ZSL, Ordered connection line OCL	Yes
Toll-switched trunks SLM, Toll connection line TCL	Yes
Two-bit CAS signaling	Yes
Single-bit CAS signaling	Yes
Two-, four-wire analog signaling	Yes
Multifrequency signaling:Pulse packet 1, 2, 3a, 3b	Yes
Multifrequency shuttle signaling:Pulse shuttle, R1.5	Yes
Pulse (decadic) signaling	Yes
ANI request and reception	Yes
ANI response (generation)	Yes
Unilateral call clearing	Yes
Bilateral call clearing	Yes
Calling party category translation	Yes
IP Telephony
Interface	10/100 BaseT
H.323 protocol, Version 5	Yes
SIP Session Initiation Protocol, RFC 3261	Yes
Telesis xSIP (eXtended SIP) protocol	Yes
FTP (File Transfer Protocol)	Yes
Adjunct protocol	Yes
XDP (Xymphony Discovery Protocol)	Yes
Dynamic DNS update client service	Yes
G.711 audio codec	Yes
G.723.1 (5.3 and 6.4kbps) audio codec	Yes
G.729, G.729A audio codec	Yes
G.711 frame length	10 to 90msec
G.723.1 frame length	30 to 90msec
G.729, G.729A frame length	10 to 90msec
Silence Suppression (VAD)	Yes
Echo Canceler G.168-2002	Yes
QoS (Tos and Diffserv)	Yes
T.30 Fax Pass-through for SIP	Yes
Integrated H.323 gatekeeper	Yes
Integrated SIP registrar	Yes
Integrated xSIP registrar	Yes
H.323 endpoints, which can register	512
SIP user agents, which can register	512
xSIP users, which can register	96 (with licensing)
VoIP-TDM gateway channels	48 (with licensing)
Programmable ports / sockets	Yes
MD5 authentication	Yes
H.235 Baseline Security Profile	Yes
H.235 Baseline Security Profile with integrity	Yes
Digest authentication	Yes
Audio (voice) encryption	AES-256 (with licensing)
Softswitch capability	Yes
IP to TDM gateway capability	Yes
TDM to IP gateway capability	Yes
H.450 supplementary services	Yes
SIP supplementary services	Yes
API (Application Program Interface)	Yes
Fidelio Interface Application Specification protocol	Yes
Automatic conversation recording for VoIP calls	Yes
Hosting Java SIP client applet	Yes

Related Readings

We recommend you to visit Telesis Wiki Pages for technical readings.