- Release & Upgrade
- Release Notice for RMS V2.5.24
- Release Notice for UMSV1.1.41
- Finder v1.0.9
- OM50G V177 P2.2
- OM20G V177 P2.2
- NeeHau Client V188.8.131.52 (with OM20/20G/50/50G)
- OM20G V177 P2
- OM50G V177 P2
- OM80E V177 P3
- What is the purpose of SIP in VoIP?
- The Difference Between PBX And PSTN
- What Is The Meaning Of Hosted Pbx ?
- How Do You Choose An IP PBX For Your Small Business?
- How To Install New Rock OM20 IPPBX-OM20g Installation
- Why are PBX's Becoming VoIP Based？
- What's the Meaning of PBX And How does a PBX system work?
- How Is Ip Pbx Different From Traditional PBX?
- How does a hotel phone system work?
- What is PSTN gateway?
- Is VoIP Phone worth it for a small business?
- The Difference Between A Ip Phone And A Voip Phone
- Can you use your old phone with VoIP?
- What Is The Sip Response Code?
- What is VoIP Server And How a VOIP Server Works
- What is SIP 500 error
- What Is Voip Gateway
- Ip-pbx Vs Voip Gateway
- Best PBX Phone System Features for Businesses
- How to Setup a VoIP System in Office
- PBX Software Features
- Traditional IP PBX configurations
- How to choose business telephony system
- IP PBX vs. Traditional PBX
- PBX IP PBX and VoIP technology Advantages
- Guide to Business VOIP PBX
- PBX phone systems for small businesses
- How Does a SIP Gateway Work?
- SIP, VOIP & IP Phones
- VoIP Phone Systems - Create the Perfect Business Phone System
- What Is a PBX Phone System
- How much business Phone System
- What is a PBX System
- Why use VOIP
- What are the advantages of VoIP services
- FXO/FXS Gateways
- Which Voip Phone System Is Right for Your Business
- How do I choose a VoIP provider
- Flexible Hotel Phone Systems From New Rock
- How Can VoIP Help Hotels Cut Cost
- Hospitality Technology Solutions
- Modern phones for hotel rooms
- VoIP to the hospitality industry
- Hotel phone system improves hotel service experience
- Why is a Hotel Phone System Important
- How Hotel Phone Systems
- The Importance Of Using Hotel Phone System
- Hotel VOIP telephone system
- Small Hotel Phone System for up to 50 Rooms
- How Hotels Use a PBX Phone System
- Application Notes
- How to Integrate MX Gateway with OM IP-PBX
- Interconnect Two PBXs with FXO Gateways
- Interconnect Two or More Extension Lines with FXS Gateways
- Connecting MX100G-S SIP-ISDN Gateway to Elastix
- Connecting MX100G-S SIP-ISDN Gateway to Asterisk
- Expanding PBX Extensions to Remote Sites through IP Network
- Multi-site Configuration for Gateways with Analog PBX
- How to Troubleshoot Caller ID Detection Issues on FXO Port
- Security Configuration Guide for New Rock OM Series IP-PBX
- Connecting FXO Gateway to Asterisk
- Connecting FXO Gateway to Elastix
- Tie Trunk Configuration for OM with Elastix
- Training Materials
- What is VoIP gateway?
- What’s the Difference between VoIP Gateway and SIP Trunk?
- Smart Switchboard Introduces Exclusive Premium Customer Services
- What's the Difference Between VoIP Gateway and ATA?
- What's the Difference Between VoIP gateway and SBC?
- New Rock’s New Gateway Security measures
- Global VoIP Gateway Service Provider
- How to Setup VoIP Gateway - A Complete Installation Guide
- What is HX&MX VoIP Gateway Default Password?
- Auto Provisioning
- Six Practices for Audio Security
- “PSTN failover” - Strong Support for High-availability IP Audio Communications
- New Rock IP-PBX: Your All-In-One IP Office Telephony System
- Connecting E1/T1-Based PBX to IP Telephony Networks
- Popular IP-PBX Features Favored by Highly Efficient Officers
- Five-star Customer Services
- Top Three Advantages of Gateways with Imbedded VPN Clients
- Low-Cost, High-Quality Gateway
- Smart FoIP
- Two Typical Applications for Telephone Networks
- IPv6’s Top Three Advantages in VoIP Applications
- MX100G-S SIP-ISDN Trunking Gateway Training
- MX Series VoIP Gateway Training
- Installation & Maintenance
- OM SIP Trunk Configuration Documentation
- NAT Traversal Service---Configuration video
- User Guide for Finder V1.0.9
- IP-PBX Installation (Video)
- OM20G&OM50G Quick Installation Guide
- OM80E Quick Start Guide
- OM200G Quick Start Guide
- OM500 Quick Installation Guide
- HX4G&MX8G Quick Reference Guide
- MX60E Quick Installation Guide
- MX120G Quick Installation Guide
- MX100G-S Quick Start Guide
- SX3000 Quick Installation Guide
- PT2400 Quick Installation Guide
- PT4800 Quick Installation Guide
Fax was designed to meet the various challenges of the PSTN, but Fax over IP (FoIP) is a different beast, and must adapt to the transmission protocols that IP utilizes. No other solution available is designed to meet the challenges presented by FoIP like Smart FoIP, which is available on all New Rock HX4G and MX8G gateways, as well as the New Rock OM20G and OM50G PBXs. By eliminating the top-two problems with FoIP; the late T.38 re-invite and the G.711 clock-synchronization problem, Smart FoIP provides near-PSTN success rates.
FoIP and T.38 BackgroundNot all T.38 (the ITU protocol for real-time faxes in IP networks since 1998) implementations exhibit the same performance in the field, even if they conform to the T.38 recommendation. You could easily have a widely interoperable T.38 with an intolerably low transaction-success rate. It is difficult to verify interoperability, and it’s even more difficult to determine performance. And to make matters worse, the parameters of T.38 performance aren’t even widely known.
Beyond interoperability, much of what we call T.38 performance is inherent in its implementation, not the specification. It’s safe to say that the best T.38 designs were developed by an engineer that has successfully fielded T.30, the protocol of terminating fax. This is because T.38 does not give any guidance on how to improve delay tolerance, for example, but, as we know, it is improved through so-called spoofing techniques implemented by skilled T.38-relay developers who thoroughly understand T.30. Better relays can handle up to five seconds of round-trip delay in the IP path.
Smart ATA attaches a V.21 modem (along with other analysis algorithms) to the media streams at the beginning of a fax call. Smart ATA analyzes the decoded V.21 data to track the T.30 states of the calling and called terminals. The called terminal will repeatedly send its initial message (DIS) until Smart ATA sends its response. Once Smart ATA receives a complete DIS, it sends its response (DCS) within 75 milliseconds. Therefore, once this calling-terminal response (DCS) is received by the called terminal, uninterruptable G.711-based modem operations have begun, and the gateways can no longer switch the session to T.38 without possible corruption of the T.30 states being maintained in the endpoint terminals.
With Smart FoIP, once Smart ATA detects the preamble to the calling fax terminal’s response, it will no longer accept the T.38 re-invite, continuing the transaction in G.711 mode and avoiding the session failures caused by the transition occurring during a modem session.
G.711 Pass-Through FaxOf course, refusing a T.38 re-invite means continuing the session in what is called “G.711 pass-through mode.” But, you may have wondered, doesn’t Smart FoIP mean more G.711 pass-through faxes? And don’t they inevitably fail? That’s a good question because the answer is yes, G.711 fax sessions do often fail unless the session includes a fax relay with Smart FoIP’s proprietary buffer-management technology.
Carriers have done a great job of virtually eliminating dropped packets, but PCM clock-synchronization problems remain. The problem results from jitter buffer under-run and over-run caused by the PCM clocks at opposite ends of the link (the endpoint terminals) not being equal, which is always the case. The question, of course, is how unequal are they and how long is the fax? The more unequal they are, the quicker the session fails. Long-enough G.711 pass-through faxes and even long T.38 sessions can fail if the jitter buffers are not effectively handled. Smart ATA includes buffer-management technology that eliminates PCM-clock-synchronization problems in G.711 pass-through and T.38 fax sessions.
In relay-to-relay T.38 operations, there are two analog PCM sample clocks: one at the remote transmitting fax and the other at the local re-modulating modem. These two clocks always have a different rate. Bits generated at the transmitting endpoint fax terminal must be re-transmitted by the off-ramp gateway’s local modem. If the remote fax is generating bits faster than the off-ramp gateway’s local modem can send them out to the fax terminal, off-ramp overflow eventually occurs. In the reverse case (off-ramp faster than transmitting fax terminal), the on-ramp modem will run dry since the off-ramp gateway is sending the bits out faster than it receives them, and T.38 relay will have to spoof some bits to keep the transmitter running (provided you have a well designed relay, of course). Underflow is not as much of a problem, since the relay can insert additional flags in V.21 data or padding bits at the end of a line of image data (Does your relay do that?). But overflow is a problem as valid data must be tossed (and modems just hate that).
- Release & Upgrade
- Application Notes
- Training Materials
- Installation & Maintenance
- Contact Us
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