
MODEM-CONVERTER E1-L
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6
Copyright © 1998-2000 Cronyx
Configuration Saving
S3-9 switch enables remote control of
modem: parameters are set by terminal
connected to control port or by network
via SNMP protocol (rack mount unit).
In remote control mode parameters are
stored in NVRAM. If remote control is
disabled NVRAM is not used and param-
eters are set only by DIP switches.
S3-9 Parameters setting
By switches only, remote control is
disabled, NVRAM is not used
By terminal, parameters are saved in
NVRAM, DIP switches are not used
Synchronization
S3-1, S3-2 switches set E1 channel syn-
chronization mode:
S3-1 S3-2 E1 channel synchronization
INT – internal oscillator
RCV – from receiver
DTE1 emulation (ETC)
DTE2 emulation (ETC, ERC)
Transmit Clock Inversion
When INT or RCV synchronization mode
is used, data signal TXD is delayed in rela-
tion to TXC clock. Summary delay is
formed by cable delay and digital interfac-
es delay of modem and connected device.
As a result of this delay errors can occur at
some data rates. The problem can be solved
by inverting the transmit clock signal us-
ing S3-6 switch:
S3-6 TXC inversion
no TXC inversion
TXC inversion
Receive Clock Inversion
When DTE2 emulation is used, the RXD
signal is delayed in relation to ERC clock.
Summary delay is formed by cable delay
and digital interfaces delay of modem and
connected device. As a result of this delay
errors can occur at some data rates. The
problem can be solved by ERC inversion
via S3-7 switch.
When DTE2 emulation is not used, the S3-
7 switch controls RXC inversion in rela-
tion to received data RXD:
S3-7 RXC or ERC inversion
no RXC or ERC inversion
RXC or ERC inversion
Use of Timeslot 16 / Scrambler
S3-3 switch controls use of E1 frame
timeslot 16 in framed mode. In unframed
mode S3-3 switch controls data scrambling.
S3-3 Framed mode: Unframed mode:
Timeslot 16 Scrambler
reserved for signaling disabled
enabled for data enabled