When starting with the AEA PK-232, there are a few commands that may come in useful especially in the pursuit of an HF Packet Station. The first is the default configuration, which I paste into my PuTTY Command line once I've made contact with the PK-232 via Serial. This may be useful for you, or you may decide the options are different ;

mycall <CALLSIGN>
VHF off
HBAUD 300
EXPERT ON
packet
daytime YYMMDDHHMMSS
BTEXT <CALLSIGN>, <CALLSIGN>-1 MBX [LOC]
CText Welcome to <CALLSIGN>PK-232, I'm not here right now, Please leave a message on <CALLSIGN>-1 Maildrop.
Mtext Welcome to <CALLSIGN>-1, PK-232MBX Maildrop
BEACON EVERY 90
mymail <CALLSIGN>-1
passall on
8Bitconv on
constamp on
mdigi on
mproto on
mstamp on
xflow off
maildrop on
mdmon on

Packet Commands

MailBox

Is the STA LED FLASHING ? Check MailBox Server, you have a message.

cmd:mdcheck
You have mail.

List Messages

(AEA PK-232M) 18396 free (B,E,K,L,R,S) >
l

Msg# Size To From @ BBS Date Time Title
3 PN 84 <CALL><CALL>04-Jul-20 14:14 test from portable station

Read Message 

(AEA PK-232M) 18396 free (B,E,K,L,R,S) >
READ 3

Msg# Size To From @ BBS Date Time Title
3 PN 84 <CALL><CALL>04-Jul-20 14:14 test from portable station
test message into MBX for <CALL>-1, TEST TEST TEST
/E

Delete Message

(AEA PK-232M) 18396 free (B,E,K,L,R,S) >
k 3
*** Done.
(AEA PK-232M) 18536 free (B,E,K,L,R,S) >
cmd:

Create or Leave a message

cmd:mdcheck

(AEA PK-232M) 18396 free (B,E,K,L,R,S) >
s ALL

Subject:
Welcome to <CALL>
Enter message, ^Z (CTRL-Z) or /EX to end

<MESSAGE FOR ALL TO RECEIVE>

/EX
Message stored as # 1

(AEA PK-232M) 18172 free (B,E,K,L,R,S) >