The Juniper Networks CTP150 Circuit to Packet platform optionally includes a replaceable CTP150–IM-SER serial interface module that can be paired with another module of the same type or a T1/E1 interface module. The serial interface module also has the option of supporting two multiservice daughter cards for 4-KHz or high-quality analog audio, or interrange instrumentation group (IRIG) signals. The four-port serial interface module supports individual cabling for each port. The CTP150 ports have small serial ports for HD-26 26-pin connectors. The software-selectable interfaces for the module are RS-232/V.24, EIA530/X.21, EIA530A, V.35, and IRIG. Software-selectable rates range from 50 bps to 12.228 Mbps. The module also includes an external clock reference port for an HD-26 connector. It is compatible with the CTP150 product line.