The AudioCodes MediaPack 1xx (112,114,118) are analog VoIP gateways.
I use an MP-112 for my old “Clubtelefon 41” payphone, as these gateways can also generate a metering pulse.

To be able to operate the device on a Fritz!Box, some special settings are necessary that do not seem logical at first glance. In general, a large number of configuration options are available, which can be overwhelming.

Fritz!Box

Hurdles

What can be very annoying when testing, the Fritz!Box has a brute force protection on the SIP server. This blocks the affected IP for 9600 seconds. So even if everything is set up correctly, a previous misconfiguration may have caused it to still not working.

There is no indication of this in the web interface, only in the support data. You can download this via Hilfe und Info -> Fritz!Box Support -> Support-Daten speichern. The entry looks like this:

Brute-Force (BF) / Denial-of-Service (DoS) attacks
---------
Brute Force: 192.168.16.126 blocked since 2025-02-04 21:02:29 (3561/9600 seconds remaining)
REGISTER sip:fritz.box 2.0
Via: SIP/2.0/UDP 192.168.16.126:5060;branch=z9hG4bKac746695174
From: <sip:xxx@192.168.16.126>;tag=1c746687486
To: <sip:xxx@192.168.16.126>
Call-ID: 329231920422025154144@192.168.16.126
CSeq: 346 REGISTER
Contact: <sip:xxx@192.168.16.126:5060>;expires=180
Max-Forwards: 70
Supported: path
Expires: 180
User-Agent: MP-112 FXS/v.6.60A.365.005
Allow: REGISTER, OPTIONS, INVITE, ACK, CANCEL, BYE, NOTIFY, PRACK, REFER, INFO, SUBSCRIBE, UPDATE
Content-Length: 0

Configuration

There is actually not much to do here, just set up a new IP telephone under Telefonie -> Telefoniegerät.
Make sure that the user name and password comply with the guidelines. However, a current Fritz!OS 8 indicates this.

IP telephone settings

AudioCodes Gateway

These settings were created using an MP-112 with firmware 6.60A.365.005.

Factory Reset

  1. Disconnect the network cable (very important!)
  2. Press and hold the reset button for 6 Seconds

Basic settings

Default IPs:
FXS and FXS-with-FXO Models: 10.1.10.10/16
FXO Models: 10.1.10.11/16

Username: Admin
Password: Admin

  1. System->Application Settings
    • NTP Server de.pool.ntp.org
    • activate DHCP
    • Submit
  2. VoIP->GW and IP to IP-> DTMF & Dialing
    • Max Digits in Phone Num: 15
    • Declare RFC2833 in SDP: no
    • 1st Tx DTMF Option: INFO(Nortel)
  3. Burn

The setting of the DTMF options has the effect that 15-digit telephone numbers can be called and IWV (“pulse dialing”) is transmitted as DTMF (“Dual-tone multi-frequency”), so that rotary dial telephones can also address IVR.

Fritz!Box SIP settings

My Fritz!Box is configured to use 192.168.15.1 as IP address.

  1. VoIP -> SIP Definitions -> Proxy & Registrations

    1. Use Default Proxy: Yes
    2. Proxy Set Table
      1. 192.168.15.1 UDP
    3. Enable Registration: Yes
    4. Proxy Name: fritz.box
    5. Registrar Name: fritz.box
    6. Registrar IP Address: 192.168.15.1
    7. Registrar Transport Type: UDP
    8. Gateway Name: fritz.box
    9. Gateway Registration Name: fritz.box
    10. Username: audiocodesmp112
    11. Password: fnWpAc7T7kzXDaAO9kyfrwuU

  2. VoIP->GW and IP to IP-> Hunt Group

    1. Endpoint Phone Number:
      1. Channels: 1
      2. Phone Number audiocodesmp112

  3. VoIP->Analog Gateway->Authentication

    1. Username: audiocodesmp112
    2. Password: fnWpAc7T7kzXDaAO9kyfrwuU

  4. VoIP->Routing->Tel to IP Routing

    1. Dest. IP: 192.168.15.1
    2. Port: 5060
    3. Transport: UDP

  5. Burn

Metering tones and pulse dialing

To get metering tones and pulse dialing working, you need to download the current configuration (Maintenance->Software Update-> Configuration file) and modify it:

[Analog Params]
#Add the following
MeteringType = 1
MinFlashHookTime = 200
FlashHookPeriod = 200
EnablePulseDialDetection = 1

Save the file and upload it again to the device.
To enable metering tones you need to define a charge codes table under VoIP-> GW and IP to IP-> Analog Gateway -> Charging -> Charge Codes.
The pulse rate is specified in 1/10 seconds.