Chapter 1. Introduction ASM-20 Installation and Operation Manual
1-6 Technical Specifications 6/4/99 13:10
characters. The remote converter will add a shorter stop bit (shorter by
12.5% or 25%) before sending the data to the remote DTE.
A suitable operation of the ASYNC to SYNC converter is selected by adjusting
the proper character length and frequency deviation setting (dip switch
bank), see Figure 2-3 and Table 2-2.
X.21 Buffer (for
X.21 interface)
To allow tail-end connection on an X-21 interface, a buffer is provided on
received data. When ASM-20 is used in external clock configuration, set
jumper JP2 to EXT. When internal or receive clock configuration is used, set
the jumper to the opposite side. See Appendix C, IR-X.21B Interface Module
for more information.
Test Pattern
Generator and
Receiver
This feature allows for easy and quick testing of the local modem as well as
the communication link. When the PATT button on the front panel is
activated, the circuit sends and checks a standard 511-bit pseudo random
pattern. If errors are encountered, the ERROR LED remains ON or blinks.
The test can be carried out in local analog loopback, in remote digital
loopback or in normal point-to-point operation opposite a remote ASM-20
modem. Press the PATT push button on the remote unit or connect a Bit
Error Rate Tester which uses the standard 511-bit pattern.
X.21 External
Clock Buffer
Option
Available with X.21 interface model only. See Appendix C, IR-X.21B Interface
Module for more information.
G.703 DTE
Interface
Available with G.703 interface model only. See Appendix B, IR-G.703
Codirectional Interface (64 kbps) for more information.
1.4 Technical Specifications
Transmission Line Type Unloaded twisted pair 19 to 26 AWG
Range See Table 1-1
Level Strap-selectable to 0 dBm or -6 dBm
Transmit Impedance 150Ω or LOW (strap selectable)
Receive Impedance 150Ω or HIGH (strap selectable)
Return Loss Greater than 15 dB
Carrier Controlled by RTS or constantly ON
Modulation Conditional diphase European Std. D1