Messages¶

Evidence tags

✅ tested in emulation · 📖 read from code or tables, not exercised · 🔶 inferred · ❓ unknown · 🔌 hardware-verified (nothing yet). See the overview.

PBX to phone¶

Order is the order on the wire. The table lists the elements a message can carry (📖 Read from the PBX's encoder tables); which ones appear depends on the message. Codeset 7 elements follow the 97 shift.

Type	Name	Codeset 0	Codeset 7
`01`	ALERTING	18 1c 1e 27 28 76 7e
`02`	CALL PROCEEDING	18 1c 1e 28
`03`	PROGRESS	08 1c 1e 28 76
`05`	SETUP	a1 04 18 1c 1e 28 34 6c 6d 70 71 74 7c 7d 7e	19
`07`	CONNECT	18 1c 1e 28 29 4c 4d 76 7c 7e
`0d`	SETUP ACKNOWLEDGE	18 1c 1e 28
`0f`	CONNECT ACKNOWLEDGE	18 28
`21`	SUSPEND REJECT	08 28
`22`	RESUME REJECT	08 28
`28`	HOLD ACKNOWLEDGE	28
`2d`	SUSPEND ACKNOWLEDGE	1c 28
`2e`	RESUME ACKNOWLEDGE	18 1c 28
`30`	HOLD REJECT	08 28
`33`	RETRIEVE ACKNOWLEDGE	18 28
`37`	RETRIEVE REJECT	08 28
`45`	DISCONNECT	08 1c 1e 28 7e
`4d`	RELEASE	08 1c 28 7e	11 19 25
`5a`	RELEASE COMPLETE	08 1c 28 29 7e	01 25 26
`62`	FACILITY	1c 27 28 6c 6d 70 71 76	02 03 04 05 08 0a 11 0b 0c 0e 22 24 25 14 1b 28
`64`	REGISTER	1c	20
`6e`	NOTIFY	27 28 76
`75`	STATUS ENQUIRY	28
`7b`	INFORMATION	a1 08 28 70	19 40
`7d`	STATUS	08 14 28

Message types the phone recognises¶

The phone validates incoming message types against a table: 62 05 01 02 07 0f 0d 45 4d 5a 7b 6e 7d 75 03 20 28 30 33 37 2d 21 2e 22 46 4e 60 79 64. In names: FACILITY, SETUP, ALERTING, CALL PROCEEDING, CONNECT, CONNECT ACK, SETUP ACK, DISCONNECT, RELEASE, RELEASE COMPLETE, INFORMATION, NOTIFY, STATUS, STATUS ENQUIRY, PROGRESS, USER INFORMATION, HOLD ACK, HOLD REJECT, RETRIEVE ACK, RETRIEVE REJECT, SUSPEND ACK, SUSPEND REJECT, RESUME ACK, RESUME REJECT, RESTART, RESTART ACK, SEGMENT, CONGESTION CONTROL, REGISTER. (📖 Read, code reading of the phone.)

Phone to PBX¶

The phone can send these messages (📖 Read from the phone's message builders; the ones marked ✅ were seen in emulation).

Type	Name	Notes
`05`	SETUP	two variants. Outgoing call: `04 03 80 90 a3`, `18 01 83`, `7d 02 91 81`, `7e 01 04`, no called number. ✅ Tested
`01`	ALERTING	answer to an incoming SETUP. ✅ Tested
`07`	CONNECT	handset lifted. ✅ Tested
`0f`	CONNECT ACKNOWLEDGE
`45`	DISCONNECT	`08 02 80 90`. ✅ Tested
`4d`	RELEASE	✅ Tested
`5a`	RELEASE COMPLETE	with cause `08 02 80 d1` when the call reference is unknown. ✅ Tested
`7b`	INFORMATION	three variants: one digit as called party number (`70 02 81 <digit>`, ✅ Tested); variants with codeset 7 elements `06`, `03`, `05` for function keys (📖 Read)
`7d`	STATUS	with call state. ✅ Tested
`75`	STATUS ENQUIRY	used for identification at registration. ✅ Tested
`25`, `26`	SUSPEND, RESUME	with call identity (📖 Read)
`24`, `31`	HOLD, RETRIEVE	(📖 Read)
`64`	REGISTER	five variants, each with facility `1c 02 95 92`, then `97` and codeset 7 elements `02` and `21` (📖 Read)
`62`	FACILITY	fourteen builders, supplementary services, content ❓ Unknown

There is no builder for CALL PROCEEDING, SETUP ACKNOWLEDGE, PROGRESS or NOTIFY, as expected for a terminal. RESTART and RESTART ACKNOWLEDGE are accepted and answered. (📖 Read.)

Cause values the phone uses¶

Standard Q.850: 16 normal clearing, 17 user busy, 30 response to STATUS ENQUIRY, 31 normal unspecified, 81 invalid call reference, 88 incompatible destination, 95 invalid message, 96 mandatory element missing, 97 message type non-existent, 99 element non-existent, 100 invalid element contents (diagnostic = element id), 102 recovery on timer expiry.