E1/T1 Messenger 2.1

The E1/T1 Messenger 2.1 terminates E1/T1 links, provides a non-blocking timeslot switch, handles ISDN LAPD signalling, records voice and signalling, detects DTMF tones and plays back voice and tones.

Data Sheet (PDF)

Product Specification (PDF)

Carrier-grade hardware

  • Dual 48VDC power inputs
  • Dual 10/100Mbit/s ethernet
  • Low power consumption (typical: 27W per 1U chassis)
  • No moving parts
  • 19" rack mount, 1U high, up to 3 modules per chassis
  • Configurations with 8, 16 and 24 E1/T1 interfaces in 1U
  • +/- 1ppm frequency source

The E1/T1 Messenger 2.1 provides the timing-sensitive parts of telecoms applications:

  • DTMF detection
  • Timeslot switching
  • L2 signalling
  • Audio prompt playback
  • Audio recording

The system is controlled via an XML-structured text api.

E1/T1 Messenger 2.1

Tone Detection

An ITU Q.24 compliant DTMF detector can be run on 120 timeslots simultaneously.

Detectors are also available for in-band signalling detection, e.g. fax tones, ring tones and busy tones.

Audio Playback

Up to one hour of audio prompts can be uploaded to the module. Prompts can be played back on 120 timeslots simultaneously. Compound prompts can be created by combining individual prompts into sequences which are played back without intermediate pauses.

Audio Streaming and Recording

Audio can be streamed to or from a TCP socket on 120 timeslots simultaneously. Streaming from E1/T1 to TCP is typically used to record messages or greetings in voicemail systems or to silently supervise calls in call-logging applications. Streaming from TCP to E1/T1 is used to replay previously recorded messages or to play text-to-speech.

Switching and conferencing

A GTH module is a non-blocking switch, i.e. all timeslots can be switched simultaneously. The switch provides simplex and duplex switching, 3-way conferences and N-way conferences.


Each module supports ISDN LAPD (Q.921) signalling for call setup.

Passive Monitoring

E1/T1 Messenger 2.1 is capable of passive monitoring in the same way as E1/T1 Monitor 3.0, except capacity is lower.