5
6
3.1.1 DCE/DTE Selector
The X.21 daughter board can be set up as DCE (default) or DTE device.
The DCE/DTE selector must be installed in the X.21 daughter board for any
configurations. The following information describes the setting for DCE/DTE.
DCE Setting:
To set a rack card as a DCE device install the DCE/DTE
(Default)
selector with the DCE arrows pointing toward the front
panel.
DTE Setting:
To set a rack card as a DTE device, install the DCE/DTE
selector with the DTE arrows pointing toward the front
panel.
3.1.2 Jumper (JP1) Setting
The X.21 daughter board operates at speeds up to 2.3Mbps. When using
the daughter board at data rates of 2Mbps or higher, clocking issues may intro-
duce bit errors. Bit errors can also occur when long cables are used to inter-
connect the modem to an X.21 terminal device (router, mux, etc.) To solve bit
error problems due to speed and/or long cables, the X.21 daughtherboard is
equipped with a jumper selector (JP1) that changes the sampling edge of the
transmit clock. Please refer to figure 1 (for Jumper JP1 Location).
The following is a brief description of JP1 setting and functionality.
Normal Setting:
Jumper shorts the two outer pins of JP1. Figure 1 shows
default postion. This position is selected when operating at
low data rate (less than 2Mbps), and using a short X.21
terminal cable.
Invert Setting:
Jumper shorts the two inner pins of JP1. This setting is
selected when operating at data rates of 2Mbps or higher
or when using long X.21 terminal cables.
APPENDIX A
PATTON ELECTRONICS MODEL IM1RC/D (X.21 DAUGHTER BD)
SPECIFICATIONS
Data Format:
Synchronous
Interface:
CCITT X.21 Module compatible with Patton
Rack Cards: 1045RC, 1092RC, 1092ARC,
1095RC, 2500RC, and 2715RC
Buffer Size:
57 Bit
Data Rate:
Supports up to 2.304 Mbps
Approvals:
FCC Part 15, Class A, European EMC Directive
89/336/EEC UL 1950 and EN60950 (as part of
the Rack System)
