LASS codes are numbers you enter on your telephone touch-pad to access special features of the telephone system.

The most well-known LASS codes are *67 to toggle Caller-ID blocking and *69, for Call Return.

Local Area Signalling Services (LASS) and Custom Calling Feature Control Codes:

Service Tone Pulse Notes

Assistance/Police 12 n/a [1]
Cancel forwarding 30 n/a [C1]
Automatic Forwarding 31 n/a [C1]
Notify 32 n/a [C1] [2]
Intercom Ring 1 (..) 51 1151 [3]
Intercom Ring 2 (.._) 52 1152 [3]
Intercom Ring 3 (._.) 53 1153 [3]
Extension Hold 54 1154 [3]
Customer Originated Trace 57 1157  
Selective Call Rejection 60 1160 (or Call Screen)
Selective Distinct Alert 61 1161  
Selective Call Acceptance 62 1162  
Selective Call Forwarding 63 1163  
ICLID Activation 65 1165  
Call Return (outgoing) 66 1166  
Number Display Blocking 67 1167 [4]
Computer Access Restriction 68 1168  
Call Return (incoming) 69 1169  
Call Waiting disable 70 1170 [4]
No Answer Call Transfer 71 1171  
Usage Sensitive 3 way call 71 1171  
Call Forwarding: start 72 or 72# 1172  
Call Forwarding: cancel 73 or 73# 1173  
Speed Calling (8 numbers) 74 or 74# 1174  
Speed Calling (30 numbers) 75 or 75# 1175  
Anonymous Call Rejection 77 1177 [5] [M: *58]
Call Screen Disable 80 1180 (or Call Screen) [M: *50]/td>
Selective Distinct Disable 81 1181 [M: *51]
Select. Acceptance Disable 82 1182 [4] [7]
Select. Forwarding Disable 83 1183 [M: *53]
ICLID Disable 85 1185  
Call Return (cancel out) 86 1186 [6] [M: *56]
Anon. Call Reject (cancel) 87 1187 [5] [M: *68]
Call Return (cancel in) 89 1189 [6] [M: *59]

Notes:

[C1] – Means code used for Cellular One service [1] – for cellular in Pittsburgh, PA A/C 412 in some areas [2] – indicates that you are not local and maybe how to reach you [3] – found in Pac Bell territory; Intercom ring causes a distinctive ring to be generated on the current line; Hold keeps a call connected until another extension is picked up [4] – applied once before each call [5] – A.C.R. blocks calls from those who blocked Caller ID (used in C&P territory, for instance) [6] – cancels further return attempts [7] – *82 (1182) has been mandated to be the nationwide code for "Send CLID info regardless of the default setting on this phone line." [M: *xx] – alternate code used for MLVP (multi-line variety package) by Bellcore. It goes by different names in different RBOCs. In Bellsouth it is called Prestige. It is an arrangement of ESSEX like features for single or small multiple line groups.

The reason for different codes for some features in MLVP is that call-pickup is *8 in MLVP so all *8x codes are reassigned *5x

LASS codes appear to be standard, but may be changed locally

Under GTE, some LASS/CLASS tones may be changed from *NN to NN#. Under pulse, GTD5 allows either NN or 11NN, but with 11NN it may conflict with a test number.

At one time LASS Codes were called CLASS Codes, for Custom Local Area Signalling Services.