
RACAL-DATACOM

VA-2450P, VA-2450S, VA-2450G, VA-2450K, VA-2455P, VA-2455S, VA-2455G,
VA-2455K

Card Type                Modem (asynchronous)
Chip Set                 Unidentified
Maximum Data Rate        2400bps
Data Bus                 External
Data Modulation Protocol Unidentified

[Image]

                                CONNECTIONS

        Function          Label              Function              Label

  RS-232/422                  CN1      Daughterboard header          P4

  DC power                    CN2      Daughterboard header          P5

  Line out                    CN3      Answer mode switch           SW3

  Header to main modem         J4      Loopback test switch         SW4
  board

  Header to main modem         J5
  board

            Note: Daughterboard included on VA-2455 models only.

                        USER CONFIGURABLE SETTINGS

                    Setting                       Label       Position

  Carrier receive level set at 0dBm to -35dBm     SWA/1          On
  (switched-line)

  Carrier receive level set at -10dBm to          SWA/1         Off
  -45dBm (leased-line)

  Phase equalization disabled                     SWA/2         Off

  Phase equalization enabled                      SWA/2          On

  Factory configured - do not alter               SWA/3         N/A

  Factory configured - do not alter               SWA/4         N/A

  Factory configured - do not alter               SWB/1         N/A

  New synchronization pulse generation            SWB/2         Off
  disabled

  New synchronization pulse generation enabled    SWB/2          On

  Modem uses internal clock source                SWB/3          On

  Modem uses external clock source                SWB/3         Off

  DTR normal                                      SWB/4         Off

  DTR forced high                                 SWB/4          On

                    USER CONFIGURABLE SETTINGS (CONT)

                  Setting                      Label         Position

  Transmit clock separated from receive        SWB/5           Off
  clock

  Receive clock looped through to transmit     SWB/5            On
  clock

  DSR forced low when modem is in test mode    SWB/6           Off

  DSR normal when modem is in test mode        SWB/6            On

  RTS normal                                   SWB/7           Off

  RTS forced high                              SWB/7            On

  50ms delay from carrier signal to raise      SWC/1            On
  DCD

  10ms delay from carrier signal to raise      SWC/1           Off
  DCD

  275ms delay from answer tone to RTS          SWC/2           Off
  disabled

  275ms delay from answer tone to RTS          SWC/2            On
  enabled

  160ms delay from CTS to RTS                  SWC/3            On

  7.1ms delay from CTS to RTS                  SWC/3           Off

  Local echo disabled                          SWC/4           Off

  Local echo enabled                           SWC/4            On

  105ms transmit to receive delay enabled      SWC/5            On

  105ms transmit to receive delay disabled     SWC/5           Off

  Factory configured - do not alter            SWC/6           N/A

  Modem will pick up the line only when        SWC/7           Off
  handset is off-hook

  Modem will pick up the line only when        SWC/7            On
  handset is on-hook

  Factory configured - do not alter             JA             N/A

  Factory configured - do not alter             JB             N/A

  Modem will disconnect on reversal of line     JD             Open
  current

  Modem will not disconnect on reversal of      JD            Closed
  line current

  Factory configured - do not alter             JE             Open

  Signal ground not connected to chassis        JF             Open
  ground

  Signal ground connected to chassis ground     JF            Closed

  Factory configured - do not alter             JG             N/A

  Factory configured - do not alter             JH             Open

  Factory configured - do not alter             JI             N/A

  Analog loopback and busy out controls on      JJ            Closed
  pins 18 and 25 disabled

  Analog loopback and busy out controls on      JJ             Open
  pins 18 and 25 enabled

  Pin 18 or 25 controls busy out only           JK             Open

  Pin 18 or 25 controls analog loopback         JK            Closed
  test and busy out

  Factory configured - do not alter             JL             N/A

  Receive clock follows transmit clock when     JM             Open
  no carrier signal is present

  Receive clock forced high when no carrier     JM            Closed
  signal is present

  SW3 functions enabled                         JP            Closed

  SW3 functions disabled                        JP             Open

  Factory configured - do not alter             JO             N/A

  Factory configured - do not alter             JQ             N/A

                    USER CONFIGURABLE SETTINGS (CONT)

                  Setting                       Label        Position

  CTS normal                                     JR            Open

  CTS follows RTS                                JR           Closed

  Auto-answer enabled                            JS            Open

  Auto-answer disabled                           JS           Closed

  Signal receive level set at switched-line    SW1B/1           On
  levels

  Signal receive level set at leased-line      SW1B/1           Off
  levels

  Secondary channel transmission               SW1B/2           Off
  attenuation set to -5dBm

  Secondary channel transmission               SW1B/2           On
  attenuation set to 0dBm

  Secondary channel local echo disabled        SW1B/3           On

  Secondary channel local echo enabled         SW1B/3           Off

  Secondary channel data rate set to 150bps    SW1B/4           On

  Secondary channel data rate set to 75bps     SW1B/4           Off

  Analog loopback test and/or busy out           W1          Pins 2 & 3
  controlled by pin 25                                        closed

  Analog loopback test and/or busy out           W1          Pins 1 & 2
  controlled by pin 18                                        closed

  Hardware configuration is used                 W2          Pins 2 & 3
                                                              closed

  Factory configuration is used                  W2          Pins 1 & 2
                                                              closed

                            LINE TYPE

       Setting                 JC                    JN

    Switched line            Closed                 Open

  2-wire leased line         Closed                Closed

  4-wire leased line          Open                 Closed

              TRANSMISSION LEVEL

        Setting                  W3

  Permissive (-10dBm)    Pins 1 & 2 closed

  Leased-line (0dBm)     Pins 2 & 3 closed

     Programmable               Open

                             DIAGNOSTIC LED(S)

   LED       Color      Status                   Condition

   TXD        Red         On             Modem is transmitting data

   TXD        Red         Off          Modem is not transmitting data

   RXD        Red         On              Modem is receiving data

   RXD        Red         Off           Modem is not receiving data

   RTS        Red         On                 RTS signal is high

   RTS        Red         Off                RTS signal is low

   CTS        Red         On                 CTS signal is high

   CTS        Red         Off                CTS signal is low

   DSR        Red         On                 DSR signal is high

   DSR        Red         Off                DSR signal is low

   DTR        Red         On                 DTR signal is high

   DTR        Red         Off                DTR signal is low

    RI        Red       Blinking              Phone is ringing

    RI        Red         Off               Phone is not ringing

   CXR        Red         On              Carrier signal detected

   CXR        Red         Off           Carrier signal not detected

                       MISCELLANEOUS TECHNICAL NOTES
 The -S and -P models are permissive and programmable switched line
 modems, respectively. The -G and -K models are 2-wire and 4-wire leased
 line modems, respectively. The defaults for the jumpers reflect these
 differences where applicable.

