Abstract: An interface device for use between a North American PCM channel bank and a CCITT PCM channel bank which allows data to stay in digital format rather than being converted to voice frequency. The interface takes care of not only the completely different serial data rates, but the different transfer characteristics of the channel data words. Synchronization is obtained by dividing the serial data stream into enough channel banks so that there is less than one-half cycle time period difference between the frequency of the incoming and outgoing data streams for one cycle of channel data words.

Abstract: A drop and insert channel bank is provided for receiving data from and inserting data onto a multichannel digital transmission line, such as a microwave radio link, between end terminals. The channel bank has a plurality of single channel units which share common equipment, including a receiver and a transmitter from and to the transmission line and a switching unit therebetween. The switching unit includes user controlled selection circuitry enabling any channel on the line to be dropped to any of the channel units, and enabling any channel to be inserted on the line from any of the channel units. Through-traffic passes through the receiver, switching unit and transmitter of the channel bank in digital form without conversion to and from analog form. Unidirectional and bidirectional modes are disclosed, including various forms of each.

Abstract: A synchronization system for data coupling apparatus is provided by delaying clocked frame identification signals instead of delaying the data in data buffer storage. Data is passed between input and output transmission lines with only the inherent delay incurred in the requisite data manipulation therebetween. The framing alignment information extracted at the input is connected to the output through a delay such that the data and framing identification signals arrive at the output at the same time and in synchronous alignment. In addition to eliminating the need for a data buffer, the system also eliminates the need for a second identification bit alignment location derivation from the output. The system utilizes an edge-aligned clock which enables substitutional insertion of data to a desired location in the bit stream.

Abstract: An angle adaptor for use in effecting coplanar routing schemes with flat ribbon cables. A unitary planar guide member around which the flat ribbon cable is folded in a desired routing angle employs hingeable arms to secure the ribbon cable to the guide member near the edges where the ribbon cable approaches and exits the member. The edge around which the ribbon cable is folded is cross-sectionally configured to eliminate sharp creases in the cable and thereby minimize cable conductor stress.