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CTP150 Serial Interface Module


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. See CTP150 Multiservice Interface Module for details.

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 (see Figure 1). The lowest-numbered port (marked 0) is at the bottom left, and the highest-numbered port (marked 3) is at the top right.

Figure 1: CTP150 Serial Interface Module
CTP150 Serial Interface Module

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. Note that only one external clock reference is required even if there are two interface modules, serial or T1/E1.

On the CLK port, differential clock signals are output on the pins 4 and 17 of the HD-26 connector. When an EIA-530A DCE-F serial cable (CTP150-CBL-DB25-DCE-F) is connected to the CLK port, the TT pins 24 and 11 of the DB25 connector output clock signals. If you configure a 32 kHz reference output, an RS-422 32 kHz clock signal is generated on the pins. Even if you disable the 32 kHz reference output and configure an external clock reference, the module expects an RS-422 clock input (of the configured frequency) on the same pins.


The external clock reference port must be the one in module slot 0, the left-most slot in the front of the CTP150 chassis.