MICROCOM, INC.
QX/4232BIS+
Card Type | Modem (synchronous/asynchronous) |
Processor | Z80 |
Processor Speed | 10MHz |
Maximum Onboard Memory | 64KB DRAM |
Maximum Data Rate | 14.4Kbps |
Data Bus | Serial |
Data Modulation | Bell 103A/212A ITU-T V.21, V.22, V.23, V.22bis, V.32, V.32bis |
Error Correction/Compression | MNP5, MNP10, V.42, V.42bis |

CONNECTIONS | |||
Function | Label | Function | Label |
Line out | CN1 | Volume control | R1 |
Line in | CN2 | Talk/Data switch | SW4 |
AC power in | CN3 | Originate/Answer switch | SW5 |
RS232/422 port | CN4 | Reset switch | SW6 |
USER CONFIGURABLE SETTINGS | ||
Setting | Label | Position |
Minimum receive signal level set to -43 dBm | JP4 | Pins 1 & 2 closed |
Minimum receive signal level set to -33 dBm | JP4 | Pins 2 & 3 closed |
í Factory configured - do not alter | JP8/A | Closed |
í Factory configured - do not alter | JP8/B | Open |
í Factory configured - do not alter | JP8/C | Open |
í Factory configured - do not alter | JP9/A | Closed |
í Factory configured - do not alter | JP9/B | Open |
í Factory configured - do not alter | JP9/C | Open |
USER CONFIGURABLE SETTINGS (CON’T) | ||
Setting | Label | Position |
Pin 1 of serial port connected to signal ground | JP10 | Pins 2 & 3 closed |
Pin 1 of serial port connected to chassis ground | JP10 | Pins 1 & 2 closed |
Pin 18 has no function | JP11/A | Open |
Modem performs local analog loopback test when pin 18 goes high | JP11/A | Closed |
í Factory configured - do not alter (for North America) | SW3/7 | On |
í Factory configured - do not alter (for North America) | SW3/8 | On |
Note: If pin 18 is enabled, busy out must be disabled. | ||
LINE TYPE SELECTION | |||
Setting | JP1/A | JP1/B | JP1/C |
Leased line (0 dBm) | Open | Open | Closed |
Permissive (-10 dBm) | Closed | Open | Open |
Programmable (-12 dBm) | Open | Closed | Open |
BUSY OUT SELECTION | ||
Setting | JP11/B | JP11/C |
Busy out enabled | Closed | Open |
Busy out disabled | Open | Closed |
Note: If busy out is enabled, pin 18 must be disabled. | ||
LEASED LINE TRANSMISSION LEVEL SELECTION | |||
Setting | SW3/1 | SW3/2 | SW3/3 |
-2 dBm | On | On | On |
-4 dBm | Off | On | On |
-6 dBm | On | Off | On |
-8 dBm | Off | Off | On |
-10 dBm | On | On | Off |
-12 dBm | Off | On | Off |
-14 dBm | On | Off | Off |
-16 dBm | Off | Off | Off |
SWITCHED LINE TRANSMISSION LEVEL SELECTION | |||
Setting | SW3/4 | SW3/5 | SW3/6 |
-2 dBm | On | On | On |
-4 dBm | Off | On | On |
-6 dBm | On | Off | On |
-8 dBm | Off | Off | On |
-10 dBm | On | On | Off |
-12 dBm | Off | On | Off |
-14 dBm | On | Off | Off |
-16 dBm | Off | Off | Off |
CONFIGURATION MODE FUNCTION | |
Mode | Function |
0 | Normal operation of modem - sets power-up defaults for various commands |
1 | Sets user profile that will be loaded at power-up |
2 | Performs diagnostic tests |
3 | Modifies factory default settings loaded by &F command |
4 | Sets power-up defaults for V.25bis synchronous and dumb synchronous modes |
Note: The QX/4232bis+ modem can be configured by switches in five modes, although command configuration is preferable when possible. Configuration modes 1, 3, and 4 can be stored in NVRAM by pressing the reset switch. Mode 0 is read on reset or power-up. Before operating, the modem’s switches should be returned to mode 0 and the appropriate settings made. | |
CONFIGURATION MODE SELECTION | ||||||
Mode | Command Set | Async/Sync | SW1/1 | SW1/2 | SW1/3 | SW1/9 |
0 | AT | Async | See mode 0 | Off | On | On |
0 | V.25bis | Async | See mode 0 | On | On | On |
1 | N/A | N/A | Off | Off | Off | On |
2 | N/A | Async | See mode 2 | On | Off | On |
2 | N/A | Sync | See mode 2 | On | Off | Off |
3 | N/A | N/A | On | Off | Off | On |
4 | V.25bis | Sync | See mode 4 | On | On | Off |
4 | None | Sync | See mode 4 | Off | On | Off |
Configuration Mode 0 - Normal Operation
USER CONFIGURABLE SETTINGS | ||
Setting | Label | Position |
í Modem goes to command mode and disconnects on low DTR | SW1/1 | On |
Modem ignores DTR | SW1/1 | Off |
í Command echo enabled | SW1/4 | On |
Command echo disabled | SW1/4 | Off |
í Auto-answer on one ring | SW1/5 | On |
Auto-answer disabled | SW1/5 | Off |
í Command sets enabled | SW1/8 | Off |
Command sets disabled | SW1/8 | On |
í Originate/Answer button determines mode | SW1/10 | On |
Force answer mode | SW1/10 | Off |
í Error correction result codes enabled | SW2/5 | Off |
Extended result codes disabled | SW2/5 | On |
í User profile loaded on reset and power up | SW2/6 | On |
Factory profile loaded on reset and power up | SW2/6 | Off |
í Switch configuration enabled | SW2/7 | Off |
Switch configuration disabled | SW2/7 | On |
í Serial port speed locked | SW2/8 | Off |
Serial port speed follows connect speed | SW2/8 | On |
Note: SW2/8 has no function in V.25bis mode. | ||
CD, CTS, AND DSR SIGNAL CONFIGURATION | ||
Setting | SW1/6 | SW1/7 |
CD, CTS, and DSR forced high | On | On |
CD normal, CTS follows CD, DSR follows OH | On | Off |
CD, CTS, and DSR forced high except at disconnect | Off | On |
í CD normal, CTS and DSR forced high | Off | Off |
FLOW CONTROL SELECTION | ||
Setting | SW2/1 | SW2/2 |
Flow control disabled | On | On |
Bidirectional XON/XOFF flow control enabled | On | Off |
í Bidirectional RTS/CTS flow control enabled | Off | On |
CTS flow control by DCE enabled | Off | Off |
CONNECT MODE SELECTION | ||
Setting | SW2/3 | SW2/4 |
Normal mode enabled | On | On |
MNP reliable mode enabled | On | Off |
í Auto-reliable mode enabled | Off | On |
LAPM or MNP reliable mode | Off | Off |
Configuration Mode 1 - User Profile
USER CONFIGURABLE SETTINGS | ||
Setting | Label | Position |
í Factory configured - do not alter | SW1/6 | N/A |
í Factory configured - do not alter | SW1/7 | N/A |
í Factory configured - do not alter | SW1/8 | N/A |
í Originate/Answer button determines mode | SW1/10 | On |
Force answer mode | SW1/10 | Off |
í Factory configured - do not alter | SW2/1 | N/A |
í Factory configured - do not alter | SW2/2 | N/A |
í Factory configured - do not alter | SW2/3 | N/A |
í Factory configured - do not alter | SW2/4 | N/A |
í Factory configured - do not alter | SW2/5 | N/A |
í Factory configured - do not alter | SW2/6 | N/A |
í Factory configured - do not alter | SW2/7 | N/A |
í Factory configured - do not alter | SW2/8 | N/A |
USER PROFILE SELECTION | ||
Setting | SW1/4 | SW1/5 |
User profile 0 | On | On |
User profile 1 | On | Off |
User profile 2 | Off | On |
User profile 3 | Off | Off |
Configuration Mode 2 - Diagnostic Testing
TOGGLE SWITCHES | ||||||
Function | Label | Function | Label | |||
Start or stop test in progress | SW1/1 | Start or stop test in progress | SW4 | |||
USER CONFIGURABLE SETTINGS | ||
Setting | Label | Position |
Modem will perform local digital loopback test | SW1/4 | Off |
Modem will not perform local digital loopback test | SW1/4 | On |
Modem will perform local analog loopback test | SW1/5 | Off |
Modem will not perform local analog loopback test | SW1/5 | On |
SW1/5 performs local analog loopback with self-test | SW1/6 | Off |
SW1/5 performs local analog loopback test | SW1/6 | On |
í Factory configured - do not alter | SW1/7 | N/A |
í Factory configured - do not alter | SW1/8 | N/A |
í Factory configured - do not alter | SW1/10 | N/A |
í Factory configured - do not alter | SW2/1 | N/A |
í Factory configured - do not alter | SW2/2 | N/A |
í Factory configured - do not alter | SW2/3 | N/A |
í Factory configured - do not alter | SW2/4 | N/A |
í Factory configured - do not alter | SW2/5 | N/A |
í Factory configured - do not alter | SW2/6 | N/A |
í Factory configured - do not alter | SW2/7 | N/A |
í Factory configured - do not alter | SW2/8 | N/A |
Note: The modem will conduct tests in synchronous or asynchronous mode according to where SW1/9 was set the last time it was reset. | ||
Configuration Mode 3 - Factory Default Modification
USER CONFIGURABLE SETTINGS | ||
Setting | Label | Position |
Verbose result codes enabled | SW1/6 | On |
Numeric result codes enabled | SW1/6 | Off |
Pins 18 and 21 have no function | SW1/7 | On |
Perform local analog loopback test when pin 18 is high, remote digital loopback test when pin 21 is high | SW1/7 | Off |
\K set to 0 | SW1/8 | Off |
\K set to 5 | SW1/8 | On |
Originate/Answer button determines mode | SW1/10 | On |
Force answer mode | SW1/10 | Off |
Inactivity timer disabled | SW2/1 | On |
Inactivity timer set to 15 minutes | SW2/1 | Off |
Modem-to-modem flow control disabled | SW2/2 | On |
Modem-to-modem flow control enabled | SW2/2 | Off |
Parity checking of flow control and escape characters disabled | SW2/3 | On |
Flow control and escape characters will be processed only if their parity matches serial port | SW2/3 | Off |
RESULT CODE CONFIGURATION | ||
Setting | SW1/4 | SW1/5 |
Result codes enabled | On | On |
Result codes disabled | On | Off |
Result codes enabled on originate only | Off | N/A |
PARITY SELECTION | |||
Setting | SW2/4 | SW2/5 | SW2/6 |
Modem will use eight data bits, no parity | On | On | On |
Modem will use seven data bits, odd parity | On | On | Off |
Modem will use seven data bits, even parity | On | Off | On |
Modem will use seven data bits, MARK parity | On | Off | Off |
Modem will use seven data bits, SPACE parity | Off | On | On |
Modem will use eight data bits, odd parity | Off | On | Off |
Modem will use eight data bits, even parity | Off | Off | On |
Modem will use eight data bits, MARK parity | Off | Off | Off |
SPEED SELECTION | ||
Setting | SW2/7 | SW2/8 |
Serial port speed set to 38.4Kbps; line speed set to 14.4Kbps | On | On |
Serial port speed set to 19.2Kbps; line speed set to 14.4Kbps | On | Off |
Serial port and line speeds set to 9600bps | Off | On |
Serial port speed set to 57.6Kbps; line speed set to 14.4Kbps | Off | Off |
Configuration Mode 4 - Synchronous Mode
USER CONFIGURABLE SETTINGS | ||
Setting | Label | Position |
Modem goes to command mode and disconnects on low-to-high DTR transition | SW1/1 | On |
Modem ignores DTR | SW1/1 | Off |
Originate/Answer button determines mode | SW1/10 | On |
Force answer mode | SW1/10 | Off |
Pins 18 and 21 have no function | SW2/3 | On |
Perform local analog loopback test when pin 18 is high, remote digital loopback test when pin 21 is high | SW2/3 | Off |
Auto-answer on one ring | SW2/7 | Off |
Auto-answer disabled | SW2/7 | On |
Modem will match connect speeds. | SW2/8 | On |
Modem will connect only at current speed. | SW2/8 | Off |
STORED NUMBER SELECTION | ||
Setting | SW1/4 | SW1/5 |
Manual dial only | On | On |
Dial first stored number when Talk/Data switch is pressed | On | Off |
Dial second stored number when Talk/Data switch is pressed | Off | On |
Dial third stored number when Talk/Data switch is pressed | Off | Off |
LINE TYPE SELECTION | |||
Setting | SW1/6 | SW1/7 | SW1/8 |
Modem is connected to switched line | On | On | On |
Modem is connected to 2-wire leased line | Off | On | On |
Modem is connected to 4-wire leased line | Off | Off | On |
Modem is connected to 2-wire leased line. After 6 seconds of receiving no input, the modem goes off-hook and attempts to connect. | On | Off | On |
Modem is connected to 4-wire leased line. After 6 seconds of receiving no input, the modem goes off-hook and attempts to connect. | On | On | Off |
CONNECT SPEED SELECTION | ||
Setting | SW2/1 | SW2/2 |
Modem will connect at 14.4Kbps | On | On |
Modem will connect at 9600bps | On | Off |
Modem will connect at 4800bps | Off | On |
Modem will connect at 2400bps | Off | Off |
CD, CTS, DSR, AND RTS SIGNAL CONFIGURATION | |||
Setting | SW2/4 | SW2/5 | SW2/6 |
CD, CTS, and DSR forced high | On | On | On |
CD, CTS, and DSR normal | On | On | Off |
CD, CTS, and DSR forced high except at disconnect | On | Off | On |
CD normal, CTS and DSR forced high | On | Off | Off |
CD, CTS, and DSR normal | Off | On | On |
CD normal, CTS follows RTS, DSR forced high | Off | On | Off |
CD and CTS use ITU-T V.13 to simulate half-duplex modes, DSR normal | Off | Off | On |
CD and CTS use ITU-T V.13 to simulate half-duplex modes, DSR forced high | Off | Off | Off |
DIAGNOSTIC LED(S) (POWER-UP) | |||
TST | OH | HS | Condition |
On | Off | Off | Firmware checksum incorrect |
On | Off | Red | RAM test failed |
On | Off | Green | Modem failed |
On | On | N/A | Modem failed |
Off | Off | Off | All tests passed |
DIAGNOSTIC LED(S) (NORMAL OPERATION) | |||
LED | Color | Status | Condition |
PWR | Unidentified | On | Power is on |
PWR | Unidentified | Off | Power is off |
TST | Unidentified | On | System error has occurred or modem is retraining |
TST | Unidentified | Blinking | Serial port is waiting to be configured |
TST | Unidentified | One blink | Data error has occurred |
TST | Unidentified | Off | Normal operation |
OH | Unidentified | On | Modem is off-hook |
OH | Unidentified | Off | Modem is on-hook |
HS | Red | On | Modem is connected at, or serial port speed is set to, 300bps |
HS | Red | 1 blink | Modem is connected at, or serial port speed is set to, 600bps |
HS | Red | 2 blinks | Modem is connected at, or serial port speed is set to, 1200bps |
HS | Red | 3 blinks | Modem is connected at, or serial port speed is set to, 2400bps |
HS | Green | On | Modem is connected at, or serial port speed is set to, 4800bps |
HS | Green | 1 blink | Modem is connected at, or serial port speed is set to, 7200bps |
HS | Green | 2 blinks | Modem is connected at, or serial port speed is set to, 9600bps |
HS | Green | 3 blinks | Modem is connected at, or serial port speed is set to, 12Kbps |
HS | Green | 4 blinks | Modem is connected at, or serial port speed is set to, 14.4Kbps |
HS | N/A | Off | Modem is connected at, or serial port speed is set to, 75bps |
DTR | Unidentified | On | DTR signal is high |
DTR | Unidentified | Off | DTR signal is low |
TXD | Unidentified | Blinking | Modem is transmitting data |
TXD | Unidentified | Off | Modem is not transmitting data |
RXD | Unidentified | Blinking | Modem is receiving data |
RXD | Unidentified | Off | Modem is not receiving data |
SUPPORTED STANDARD COMMANDS |
Basic AT Commands |
+++, ‘comma’, A/ |
A, B, E, H, I, L, M, O, P, Q, T, V, W, X, Y, Z |
&D, &F, &G, &M, &P, &T, &W, &X, &Y, &Z |
Extended AT Commands |
\A, \B, \C, \E, \J, \N, \Q, \T |
%A, %C, %E, %F, %G |
Special AT Commands |
-J, *H, )M, @M, :E |
S-Registers |
S0, S1, S2, S3, S4, S5, S6, S7, S8, S9, S10, S12, S14, S16, S18, S22, S23, S25, S26, S27 |
Note: See MHI documentation for complete information. |
Proprietary AT Command Set
COMMAND SET - V.25bis | |
Type: | Immediate |
Format: | [cmds] \M |
Description: | Enables the V.25bis command set. |
DISPLAY SWITCH SETTINGS | ||
Type: | Immediate | |
Format: | AT [cmds] %Sn [cmds] | |
Description: | Displays the modem’s switch settings. | |
Command | Function | |
%S0 | Display settings of SW1/1-SW1/10. | |
%S1 | Display settings of SW2/1-SW2/8. | |
%S2 | Display settings of SW3/1-SW3/8. | |
LEASED LINE CALL RESTORAL | ||
Type: | Configuration | |
Format: | AT [cmds] )Pn [cmds] | |
Description: | Selects whether the modem will attempt to reconnect with a dial backup call to a leased line MNP reliable mode connection that has terminated abnormally. If the dial backup reconnects successfully, the call will proceed as if it had not disconnected. | |
Command | Function | |
)P0 | Leased line call restoral disabled. | |
í )P1 | Leased line call restoral enabled. | |
LEASED LINE COMPROMISE EQUALIZER | ||
Type: | Configuration | |
Format: | AT [cmds] )En [cmds] | |
Description: | Selects whether the compromise equalizer will be used for leased line V.32 and V.32bis connections. | |
Command | Function | |
í )E0 | Compromise equalizer disabled. | |
)E1 | Compromise equalizer enabled. | |
LEASED LINE DIAL BACKUP | ||
Type: | Configuration | |
Format: | AT [cmds] :Nn [cmds] | |
Description: | Selects whether the modem will attempt to connect to the first stored number with a switched line connection if the leased line connection fails. | |
Command | Function | |
:N0 | Dial backup disabled. | |
í :N1 | Dial backup enabled. | |
LEASED LINE DIAL BACKUP IN ANSWER MODE | ||
Type: | Configuration | |
Format: | AT [cmds] )Cn [cmds] | |
Description: | Selects whether the modem is allowed to execute a dial backup if it is in answer mode. | |
Command | Function | |
)C0 | Dial backup disabled in answer mode. | |
í )C1 | Dial backup enabled in answer mode. | |
LEASED LINE MAXIMUM RETRAIN COUNTER | |
Type: | Configuration |
Format: | AT [cmds] :Gn [cmds] |
Description: | Sets the number of times the modem is allowed to retrain in the time specified by the :H command before it attempts a dial backup connection. |
LEASED LINE MAXIMUM RETRAIN TIME | |
Type: | Configuration |
Format: | AT [cmds] :Hn [cmds] |
Default: | 0 |
Range: | 0 - 255 |
Unit: | 1 minute |
Description: | Sets the amount of time in which the modem is allowed to retrain the number of times specified by the :G command before it attempts a dial backup connection. |
LEASED LINE ORIGINATE MODE TIMER | |
Type: | Configuration |
Format: | AT [cmds] &Vn [cmds] |
Default: | 5 |
Range: | 0 - 90 |
Unit: | 1 minute |
Description: | Sets the amount of time that the originating modem waits for an answer before attempting a dial backup. |
LEASED LINE QUALITY | |
Type: | Immediate |
Format: | AT [cmds] )F [cmds] |
Default: | N/A |
Range: | 0 - 65535 |
Unit: | N/A |
Description: | Displays the poorest quality of the phone line this connection. Higher numbers indicate a poorer connection. |
LEASED LINE QUALITY CLEAR | |
Type: | Configuration |
Format: | AT [cmds] :Y [cmds] |
Description: | Clears the line quality value reported by )F so that the current line quality may be monitored. |
LEASED LINE RESTORAL | ||
Type: | Configuration | |
Format: | AT [cmds] )Ln [cmds] | |
Description: | Selects whether the modem will attempt to restore a leased line connection while connected with a dial backup connection. | |
Command | Function | |
)L0 | Modem will not attempt to restore leased line connection. | |
í )L1 | Modem will attempt to restore leased line connection. | |
LEASED LINE RESTORAL CARRIER TIMER | |
Type: | Configuration |
Format: | AT [cmds] )Wn [cmds] |
Default: | 20 |
Range: | 0 - 255 |
Unit: | 1 second |
Description: | Sets the amount of time that the modem waits for a carrier after attempting to restore a leased line connection. If this time expires the modem will begin a dial backup again. |
LEASED LINE RESTORAL DELAY | |
Type: | Configuration |
Format: | AT [cmds] )Xn [cmds] |
Default: | 60 |
Range: | 0 - 60 |
Unit: | 1 minute |
Description: | Sets the amount of time that the modem waits after a successful dial backup to check the leased line to see if service has been re-established. |
LEASED LINE RESTORAL RETRY DELAY | |
Type: | Configuration |
Format: | AT [cmds] )Yn [cmds] |
Default: | 40 |
Range: | 0 - 255 |
Unit: | 1 second |
Description: | Sets the amount of time after a failed attempt to re-connect to the leased line, and while it is performing a dial backup, that the modem watches for a carrier on the leased line. If no carrier is detected within this time the modem proceeds with the dial backup. |
LEASED LINE RESTORE | |
Type: | Immediate |
Format: | AT [cmds] )B [cmds] |
Description: | Initiates a leased line restoral. |
LINE TYPE | ||
Type: | Configuration | |
Format: | AT [cmds] &Ln [cmds] | |
Description: | Selects what type of line the modem is connected to and whether it will attempt to automatically re-connect. | |
Command | Function | |
í &L0 | Modem is connected to switched line. | |
&L1 | Modem is connected to 2-wire leased line. | |
&L2 | Modem is connected to 4-wire leased line. | |
&L3 | Modem is connected to 2-wire leased line. After 6 seconds of receiving no input, the modem goes off-hook and attempts to connect. | |
&L4 | Modem is connected to 4-wire leased line. After 6 seconds of receiving no input, the modem goes off-hook and attempts to connect. | |
OPERATING MODE | ||
Type: | Configuration | |
Format: | AT [cmds] $Sn [cmds] | |
Description: | Selects whether the modem will operate in asynchronous or synchronous mode. | |
Command | Function | |
í $S0 | Determined by SW1/9. | |
$S1 | Force asynchronous mode. | |
$S2 | Force synchronous mode. | |
Proprietary V.25bis Command Set
COMMAND SET - AT | |
Type: | Immediate |
Format: | ATZ |
Description: | Enables the AT command set. |
CONNECTION SECURITY - PASSWORD SELECTION (ASYNCHRONOUS MODE) | |
Type: | Configuration |
Format: | PSW |
Description: | Changes the connection password. The user will be prompted to enter the old and new passwords. Passwords must be exactly five characters, case insensitive. |
CONNECTION SECURITY - PASSWORD SELECTION (SYNCHRONOUS MODE) | |
Type: | Configuration |
Format: | PSWxxxxx;yyyyy |
Description: | Changes the connection password. The xxxxx represents old connection password, and the yyyyy is the new connection password. Passwords must be exactly five characters, case insensitive. |
See MICROCOM, INC. DESKPORTE FAST for a full command summary.