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 |

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 board | J4 | Loopback test switch | SW4 | |||
Header to main modem board | J5 | |||||
Note: Daughterboard included on VA-2455 models only. | ||||||
USER CONFIGURABLE SETTINGS | ||
Setting | Label | Position |
Carrier receive level set at 0dBm to -35dBm (switched-line) | SWA/1 | On |
Carrier receive level set at -10dBm to -45dBm (leased-line) | SWA/1 | Off |
í Phase equalization disabled | SWA/2 | Off |
Phase equalization enabled | SWA/2 | On |
í Factory configured - do not alter | SWA/3 | N/A |
í Factory configured - do not alter | SWA/4 | N/A |
í Factory configured - do not alter | SWB/1 | N/A |
í New synchronization pulse generation disabled | SWB/2 | Off |
New synchronization pulse generation enabled | SWB/2 | On |
í 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 (CON’T) | ||
Setting | Label | Position |
í Transmit clock separated from receive clock | SWB/5 | Off |
Receive clock looped through to transmit clock | SWB/5 | On |
í DSR forced low when modem is in test mode | SWB/6 | Off |
DSR normal when modem is in test mode | SWB/6 | On |
í RTS normal | SWB/7 | Off |
RTS forced high | SWB/7 | On |
í 50ms delay from carrier signal to raise DCD | SWC/1 | On |
10ms delay from carrier signal to raise DCD | SWC/1 | Off |
í 275ms delay from answer tone to RTS disabled | SWC/2 | Off |
275ms delay from answer tone to RTS enabled | SWC/2 | On |
í 160ms delay from CTS to RTS | SWC/3 | On |
7.1ms delay from CTS to RTS | SWC/3 | Off |
í Local echo disabled | SWC/4 | Off |
Local echo enabled | SWC/4 | On |
í 105ms transmit to receive delay enabled | SWC/5 | On |
105ms transmit to receive delay disabled | SWC/5 | Off |
í Factory configured - do not alter | SWC/6 | N/A |
í Modem will pick up the line only when handset is off-hook | SWC/7 | Off |
Modem will pick up the line only when handset is on-hook | SWC/7 | On |
í Factory configured - do not alter | JA | N/A |
í Factory configured - do not alter | JB | N/A |
Modem will disconnect on reversal of line current | JD | Open |
Modem will not disconnect on reversal of line current | JD | Closed |
í Factory configured - do not alter | JE | Open |
í Signal ground not connected to chassis ground | JF | Open |
Signal ground connected to chassis ground | JF | Closed |
í Factory configured - do not alter | JG | N/A |
í Factory configured - do not alter | JH | Open |
í Factory configured - do not alter | JI | N/A |
í Analog loopback and busy out controls on pins 18 and 25 disabled | JJ | Closed |
Analog loopback and busy out controls on pins 18 and 25 enabled | JJ | Open |
í Pin 18 or 25 controls busy out only | JK | Open |
Pin 18 or 25 controls analog loopback test and busy out | JK | Closed |
í Factory configured - do not alter | JL | N/A |
í Receive clock follows transmit clock when no carrier signal is present | JM | Open |
Receive clock forced high when no carrier signal is present | JM | Closed |
í SW3 functions enabled | JP | Closed |
SW3 functions disabled | JP | Open |
í Factory configured - do not alter | JO | N/A |
í Factory configured - do not alter | JQ | N/A |
USER CONFIGURABLE SETTINGS (CON’T) | ||
Setting | Label | Position |
í CTS normal | JR | Open |
CTS follows RTS | JR | Closed |
í Auto-answer enabled | JS | Open |
Auto-answer disabled | JS | Closed |
Signal receive level set at switched-line levels | SW1B/1 | On |
Signal receive level set at leased-line levels | SW1B/1 | Off |
í Secondary channel transmission attenuation set to -5dBm | SW1B/2 | Off |
Secondary channel transmission attenuation set to 0dBm | SW1B/2 | On |
í Secondary channel local echo disabled | SW1B/3 | On |
Secondary channel local echo enabled | SW1B/3 | Off |
í Secondary channel data rate set to 150bps | SW1B/4 | On |
Secondary channel data rate set to 75bps | SW1B/4 | Off |
í Analog loopback test and/or busy out controlled by pin 25 | W1 | Pins 2 & 3 closed |
Analog loopback test and/or busy out controlled by pin 18 | W1 | Pins 1 & 2 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. |