US-based joint venture Granger-Telettra Inc has introduced a digital multiplexer, the DTI 45, which provides drop and insert capability for 45Mbps networks. It can access any channel or signal in the backbone network so that it can select combinations of 64Kbps timeslots, DSOs, 1.544Mbps timeslots, DS1s, and 6.3Mbps, DS2s, for customer access. Compatible with microwave radio, fibre optic or DSX3 interfaces, the DTI 45 is claimed to eliminate the need for back-to-back M13s, T1 digital cross connect, back-to-back channel banks or separate T1 drop and insert multiplexers. It is designed for low to medium density applications, and enables signals to be dropped or inserted into 45 Mbps networks. A primary shelf accesses up to 14 DSO’s or DS1s and/or DS1s or DS2s and the product can manipulate the lower level signal components in a DS3 bit stream. Additional features of the DTI 45 include field and remote programmable channel selection; full 1+1 loopback protection on both high and low speed sides; up to 56/64 Kbps DSO data speed; bidirectional access to high speed transmission paths; and inclusion of alarm, monitor and control unit. The DTI is priced from about $4,600 plus $500 per channel drop and is available now in the US. Granger-Telettra has also announced a digital terminal multiplexer for low to medium density terminations, called the DTM 45. Its field programmable network interfaces are for 12.6Mbps, 26Mbps or 45Mbps and can accommodate any mix of up to 28 DSI, 14 DSIC or seven DS2 input-output ports. Its line interfaces can be configured for fibre optic, radio or DS3. It also features 1++1 high level protection, laser light source, low 70-watt power consumption, AMC unit and optional orderwire and service channels. Both are available in compact 19 rack mountings. Granger-Telettra is a US-based joint venture between DSC Granger Associates, a subsidiary of DSC Communications Corp and Telettra USA.