VX-2039 - Dual ISDN 4-Wire Audio Adaper


The VX-2039 4-Wire Adapter for ISDN-2 (basic rate ISDN) provides two independent 4-wire audio circuits for talkback, cue and other applications on a single ISDN-2 installation. It is available in a 1U high rackmount housing. As dedicated circuits are withdrawn, the VX-2039 and ISDN provide an alternative that is more flexible and less costly.

The VX-2039 performs the same role on ISDN as a hybrid does on PSTN lines, but without any of the complications of line balancing. The two independent 4-wire circuits are presented at line level on XLRs for simple integration with existing communications equipment. Both ports can be used for conventional telephone calls to PSTN numbers via ISDN, and to provide 4-wire circuits directly over ISDN to PSTN hybrids.

A standard TouchTone telephone (not supplied) is used to set up outgoing calls, which are automatically routed to the 4-wire circuit. Incoming calls can also be answered automatically. Front panel LEDs indicate when each line is in use. To facilitate integration into studio mixing desks, remote answering and line status indication are provided via a D-connector on the rear panel.

On a digital circuit such as ISDN, incoming and outgoing audio signals are transmitted and received as full duplex data, providing a true 4-wire circuit end-to-end with no need for hybrid balancing. Two independent circuits to different locations can be established at the same time, using the two B-channels of the ISDN-2 circuit.

The audio encoding process is G.711, the ITU standard for telephone calls. Thus, as well as providing four-wire links between two ISDN numbers, the VX-2039 can also establish a 4-wire link between an ISDN number and a PSTN number equipped with a telephone hybrid. In addition, a standard TouchTone telephone can be used to place normal phone calls between the VX-2039 and PSTN subscribers.

4-Wire Audio:
Channels 2 channels (1 per ISDN bearer)
4-wire audio in Female 3-pin XLR socket (per channel)
4-wire audio out Male 3-pin XLR socket (per channel)
4-wire audio levels Line level (0dBu) in and out
Bandwidth 300Hz to 3.4kHz (ITU G.711)
Network Basic rate ISDN (ISDN-2)
Network connection RJ-45 socket (S-bus)
Local call routing ISDN multiple subscriber numbering (MSN)
Call compatibility ITU G.711 to any telephone number
Digital 4-wire path to ISDN numbers
4-wire PSTN audio requires a remote hybrid
Dialling Standard DTMF telephone dialling
Telephone connections Dual RJ-11 sockets (BT adapters provided) - (front and rear panels of rackmount model)
Call answering Switchable manual or automatic seize
Manual - via telephone
Automatic - direct to 4-wire in/out
VX-2039R 1U high 19" rackmount (225mm deep)
LED indicators Power, ISDN present, line in use (x2)
Power supply 230V AC IEC inlet (rackmount)