Asterisk Channel Bank

A channel bank converts a group of FXS or FXO interfaces to a T1 or higher speed interface. There are now a few channel banks that will convert to an Ethernet interface instead of T1.

What to consider when selecting a channel bank: Channel Bank Checklist


General note: good solid gear, just watch for echo/am radio stations
  • Total Access 750
    • FXO Interfaces: supports far end disconnect supervision, supports CallerID detect, no impedance matching, possible echo, subject to AM RF induction interferance, if close to high power AM Radio Station (try standard low-pass DSL filters to correct this,)
    • FXS Interfaces: no known issues
  • TSU 600/600e
    • reported to work OK, requires firmware L2revK
    • FXO Interfaces: supports far end disconnect supervision, no impedance matching, minimized echo
    • FXS Interfaces:no known issues

Allied Telesyn VoIP Access Device

  • This is a 24-port FXS 1u device, conveniently presented as a single RJ-21 TELCO connector.
  • Supports:
    • G.711/G.723.1/G.729
    • T.38
  • Asterisk compatibility unknown

Asterisk as CHANNEL BANK

Carrier Access

  • ADIT 600
    • excellent gear perfect with Asterisk
    • FXO Interfaces: supports far end disconnect supervision, supports CallerID detect, impedance matching, minimized echo
    • FXS Interfaces: supports callerid and callwaiting, doesn't seem to support callwaiting callerid, someone correct if this is wrong.
      • CMG card provides an Ethernet MGCP interface as an alternative to T1.
      • NOTE: CMG card ONLY supports FXS at this time!!!
    • has a feature called dynamic impedance matching which really seems to help eliminate echo at the source.
  • Access Bank I
    • ?? not a great buy
    • FXO Interfaces: NO FAR END disconnect supervision on inbound FXO calls, flakey CallerID detect (users rpt no callerd on some ab1's) , no impedance matching,
      • If you have an Access Bank I, you can do "busydetect=yes" "busycount=16" "hanguponpolarityswitch=yes" in zapata.conf in order to achieve the next best thing to far end disconnect supervision. After the "If you'd like to make a call, please hang up and try again" message ends, the really loud cadence which follows will trigger the busydetect and hang up the channel. It's also a good idea to set an absolute timeout on calls (say, four hours or so) so even in a worst case scenario the channel will hang up eventually.
    • FXS Interfaces:?? known issues
    • Discontinued (Manufacturing AND parts availability) by Carrier Access November 2004.
  • AccessBank II
    • reported to work OK
    • FXO Interfaces: ?? CallerID detect (users rpt works some calls others not) , no impedance matching, possible echo
    • FXS Interfaces: no known issues
    • Discontinued (Manufacturing AND parts availability) by Carrier Access November 2004.


Multi Service Multiplexer FMXM-16 (Versatile 120 channels Channel Bank)

  • Four multiplexers in one 19'' subrack
  • One control unit manages four multiplexers (four E1 streams/spans)
  • Full cross-connect of all time slots and channels
  • 14 user slots in one 19'' subrack
  • Software management
  • Arbitrary Time Slot Assignment
  • Drop/Insert options
  • Modular design can be applied in various flexible network and user applications
  • Supports many protocols for data transmission
  • Extensive multiplexing and cross-connecting functions combined with a large number of voice and data transmission interfaces
  • Applications – for various combinations of integrated services (POTS, ISDN-BRA, data etc.)
  • Support of all analogue interfaces
  • Support of a wide range of digital interfaces
  • Built-in BER measuring instrument for each digital channel. Built-in tone generator for each voice channel.
  • Full Asterisk support
  • Hardware filtering of Hook On/Off glitches around the Ring Pulses
  • Arbitrary mixture of FXS and FXO channels on each span
  • Up to 120 channels in one subrrack or mixture with V.35, ISDN-NT, ISDN-LT or other type of TDM channels

When used with the new TDMoE Control Unit which implements four (4) TDMoE spans up to 31 channels each, one can realize all TDM features metioned above on LAN/MAN networks. As well the Multi-service Multiplexer FMXM-16 can be used as TDMoE channel bank for various soft switch or SOHO applications.


  • NetChannel-60
    • NetChannel-60 is a carrier grade equipment which converts up to (24/30)*2 analog (FXO/FXS) interfaces to (T1/E1)*2 interfaces.
    • It supports 7 CAS's. Perfect for South Korea Telcos and Asterisk. Probably, it supports all Europe and North America Telcos.
    • NetChannel-60 consists of a line interface card, a optional remote management card, a optional line characteristics measurement card, two redundant DC power modules, up to 10 (FXO/FXS) interfaces cards in a standard 3U rack.
    • All cards and modules are hot swappable.
    • SQL back ended GUI for remote management are used for selecting T1/E1 interfaces, selecting CAS's, monitoring status, alarming failures, reporting electrical characteristics (R, L, C) of lines and testing functionality.

    • NetCore-04 is an IP-enabled PBX consists of four NetChannel-60 and a full featured secure Asterisk box interacting with SER and GnuGK.

Mainstreet 3624

Place Holder reminder anyone with experience please pop some notes in
  • NewBridge Mainstreet 3624 (Now Alcatel)
    • Manual:
    • FXO Interfaces: FXO Interfaces are LGE Modules. Try to make sure your LGE module is ver. 03 (right-most numbering of the model/revision number). 01 will go -7 - 0+ tx/rx levels and will have very noticable interference. 03 is known to work.
    • FXS Interfaces: FXS Interfaces are defined as LGS Modules.
    • Cabling: If you are going from Newbridge to T100P, use a T1-Rollover cable to connect TX to RX. If this is not done, you will continue to be red on the T100P. See *Cable Info
    • Echo: Echo from a 7940G <-> Asterisk <-> T100P <-> 3624 <-> PSTN seems to be a non-issue.
    • Define span as: zaptel.conf/span=1,0,0,esf,b8zs
    • Define 3624 as: ESF B8ZS
    • LGE/FXO - Troubleshooting Ghosts: If you have an inbound call that is not hanging up, make sure your loopstart (LS) or groundstart (GS) settings are set to what will work with your local central office, on the LGE modules.
    • Login Problems: Try level 5, default password is 'mainstreet'.


  • Fully compatible with Asterisk or any standard T1 interface
  • Three models: 24-port FXS, 24-port FXO, and modular.
    • Modular increments 4 ports FXS or FXO
  • Supports V.35 channelized data
  • Rack-mountable in both 19" and 23" racks (2U). Also wall-mountable.
  • Supports 110V, 220V, and -48V power
  • 4x40 LCD shows real-time status of T1 and analog channels. Also used for additional configuration.
  • Easy setup - AutoT1â„¢ detects signaling and other T1 characteristics and configures the unit accordingly
  • All necessary cables and documentation included.
  • Experienced technical staff are more than willing to assist, no matter where the unit was purchased.
  • Tested and guaranteed to work with Asterisk.
    • Popular among both novice and experienced alike due to its quick and easy set-and-forget setup.
  • Restores configuration from flash memory upon power-up ensuring minimal downtime in the event of a power-failure.
  • Running the latest firmware ensures maximum performance and operation, especially with Asterisk.
    • Note: Channel banks ordered through distributors may not have the latest firmware installed. Contact Rhino for instructions on obtaining the latest version. Upgrading is quick and easy.
  • Basic Asterisk signaling setup (adjust according to your setup):
;Span 1
;Modular unit, first card is FXO
;Modular unit, 4 FXS cards

;First 4 channels are the FXO modular card
signalling = fxs_ks
;Next 16 channels are the 4 modular FXS cards
signalling = fxo_ls

TDMoE multiplexor / Ethernet channel bank

TDM over Ethernet technology offers standard, convenient and cost effective way of carrying voice services over existing Ethernet infrastructure, saving the cost of demanding T1/E1 and SDH equipment. TDMoE protocol delivers quality of services unattainable for VoIP protocols such as SIP, H323 and Skype, maintaining full TDM advantages.

  • 1 Ethernet Interface, 32 RJ-45/11 Interfaces, 1 Console
  • Employs native Asterisk® TDMoE protocol
  • No additional software is needed. Works with Asterisk out of the box
  • 2x16 LCD with yellow/blue backlight for information and diagnostics
  • Seen as ZAP device by the Asterisk switch
  • Regular telephone interface with DTMF tone dialing (pulse dialing is not supported in FXS!)
  • 10BaseT Ethernet port compatible with all 10/100/1000 networks
  • CallerID 100% supported
  • Fax sending and reception 100% supported
  • Reverse polarity (Disconnect supervision) is supported
  • Small form-factor design (19", 1U)
  • Works as master or slave Asterisk clocked device
  • Automatic failover between two Asterisks
  • Remote configuration, status monitoring and firware upgrade
  • Power supply voltage: 220/110V AC / 48V DC
    • Power consumption: 20W
    • Peak power consumption: 40W

VINA Integrator/Larscom Integrator 300/Lucent ConnectReach

These are all the same thing. No details yet on whether they work with Asterisk or not. Two T1, single Amp50 (FXO/FXS, supposedly software-selectable), Ethernet.
    • Analog FXS Interfaces: Groups of 8 upto 24 ports (see article for details)
    • CallerID on FXS Tested and working.
    • FSK Message waiting indication did not work out of box. I have not investigated settings or options to fix.


  • Astribank - USB Channel Bank For Asterisk
  • Designed specifically for Asterisk systems
  • All Astribank models connect via USB 2.0 - NO T1/E1 card required, NO PCI slot required
  • Built of 8 port FXS/FXO modules and 1/2/3/4/8 BRI ISDN modules
  • Up to 32 analog ports (FXS/FXO) per single unit
  • Rack-mountable in 19" racks (1U).
  • Supports 110V and 220V power
  • LEDs show status of each channel
  • Easy setup - no need to open panels or shut down server
  • All necessary cables and documentation included.
  • Support by Xorcom professional engineers
  • The Astribank driver is part of the official release of Zaptel
  • Multiple units may be connected via a single USB 2.0 port (using USB 2.0 hub)
  • Supports caller ID
  • Supports MSI (Message Waiting Indication) for analog phones
  • 5 REN ringing generator
  • Up to 6,000 feet line length (1 REN) – 3 REN for 4,000 feet line
  • 2 output ports (relays) enable external units activation from the dial plan (alarm systems, gates etc.) - optional
  • 4 input ports enable automatic dialing triggered by external events (receiving a call when alarm goes off etc.) - optional


Make sure you know what you're buying, use as FXS interface is OK
  • Z-PLEX-10-24S/O (actually it's not avalible from, you should use mirror at WebArchive
    • FXO Interfaces: flakey far end disconnect supervision, NO CallerID detect, no impedance matching, possible echo
    • FXS Interfaces: No Forward Disconnect on FXS
    • Supports 110V, 220/230V, and -48V power (DC and AC power could be used simultaneously sharing load and working as backup of each other).
    • Rack-mountable in 19" rack (1U). Also wall-mountable and table mountable.

Price on Ebay is about USD 120-150 for used channel bank. After updating to the latest software it seems to work OK. The firmware could be found on Zhone's FTPsite * Upgrade from 1.0.1 to 1.0.9 preserves all configs in CB, so it's safe to do upgrade.

See Also

Created by: jht2, Last modification: Wed 27 of Jan, 2010 (07:11 UTC) by rbridger
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